Amplification and analysis of whole genome and whole transcriptome libraries generated by a DNA polymerization process
11492663 · 2022-11-08
Assignee
Inventors
- Emmanuel Kamberov (Ann Arbor, MI)
- Tong Sun (Houston, TX)
- Eric Bruening (Chelsea, MI)
- Jonathon H. Pinter (Ypsilanti, MI)
- Irina Sleptsova (Ann Arbor, MI)
- Takao Kurihara (Ann Arbor, MI)
- Vladimir L. Makarov (Ann Arbor, MI)
Cpc classification
C12Q2525/15
CHEMISTRY; METALLURGY
C12Q2525/15
CHEMISTRY; METALLURGY
C12Q2525/179
CHEMISTRY; METALLURGY
C12Q2525/161
CHEMISTRY; METALLURGY
C12Q1/6876
CHEMISTRY; METALLURGY
C12Q2525/179
CHEMISTRY; METALLURGY
C12N15/1093
CHEMISTRY; METALLURGY
C12Q1/6806
CHEMISTRY; METALLURGY
C12Q2525/161
CHEMISTRY; METALLURGY
International classification
C12Q1/6876
CHEMISTRY; METALLURGY
C12Q1/6806
CHEMISTRY; METALLURGY
Abstract
The present invention regards a variety of methods and compositions for whole genome amplification and whole transcriptome amplification. In a particular aspect of the present invention, there is a method of amplifying a genome comprising a library generation step followed by a library amplification step. In specific embodiments, the library generating step utilizes specific primer mixtures and a DNA polymerase, wherein the specific primer mixtures are designed to eliminate ability to self-hybridize and/or hybridize to other primers within a mixture but efficiently and frequently prime nucleic acid templates.
Claims
1. A kit, comprising: a container; and a) a population of primers configured to amplify a whole genome or whole transcriptome present in the container, wherein the population of primers are non-self-complementary and non-complementary to other primers in the population, and comprise in a 5′ to 3′ orientation a constant region and a variable region that are adjacent to each other, wherein the constant region sequence has a known sequence that is constant among a plurality of primers of the population and the variable region sequence is degenerate among the plurality of primers of the population, wherein the sequence of the constant region comprises at least 70% of two types of non-complementary nucleotides selected from the group consisting of adenines and guanines; adenines and cytosines; guanines and thymidines; and cytosines and thymidines, and the sequence of the variable region comprises greater than 50% non-complementary nucleotides selected from the group consisting of adenines and guanines; adenines and cytosines; guanines and thymidines; and cytosines and thymidines; wherein the constant region is 6-100 nucleotides in length; b) at least one target-specific primer for targeted amplification; c) at least one nested primer for further amplifying amplicons generated by the targeted amplification; and d) a set of instructions for using the kit to detect copy number variation (CNV), genotype single nucleotide polymorphism (SNP), genotype micro-satellite, detect insertion and/or deletion, determine zygosity, or detect mutation(s), wherein the sequence of the constant and variable regions will not cross-hybridize or self-hybridize under conditions described in the set of instructions.
2. The kit of claim 1, wherein amplicons generated by the primers in (a)-(c) are at least 100 base pairs long.
3. The kit of claim 1, wherein the primers in (a)-(c) comprise at least 10 nucleotides.
4. The kit of claim 1, wherein the primers in (a)-(c) comprise at least one modified nucleotide.
5. The kit of claim 1, wherein melting temperature of the primers in (a)-(c) is at least 45 degrees Celsius.
6. The kit of claim 1, wherein the at least one nested primer is complementary to amplicons generated by the targeted amplification.
7. The kit of claim 1, wherein the at least one target-specific primer is specific to one or more target sequences.
8. The kit of claim 1, wherein the at least one target-specific primer does not comprise an adapter sequence.
9. The kit of claim 1, wherein the set of instructions instructs a user to carry out a first series of polymerase chain reaction steps using the population of primers and the at least one target-specific primer followed by a second series of polymerase chain reaction steps using the at least one nested primer.
10. The kit of claim 9, wherein the set of instructions further instructs the user to sequence amplicons generated at the end of the second series of polymerase chain reaction steps using a sequencer.
11. The kit of claim 1, wherein the kit further comprises reagents selected from the group consisting of a cell lysis reagent, magnesium salts, a ligase, a polymerase, a reverse transcriptase, betaine and a kinase.
12. The kit of claim 1, wherein the kit is configured for use with a sample comprising nucleic acid molecules: DNA or RNA.
13. The kit of claim 12, wherein the sample is selected from the group consisting of blood, serum, plasma, cerebrospinal fluid, cheek scrapings, nipple aspirate, biopsy, semen, urine, feces, hair follicle, saliva, sweat, immunoprecipitated or physically isolated chromatin, a single cell or a plurality of cells.
14. The kit of claim 12, wherein the kit is configured for obtaining genomic copy number, sequence information, allelic variation information, cancer diagnosis, prenatal diagnosis, paternity information, disease diagnosis, detection, monitoring, or treatment information using the sample.
15. The kit according to claim 1, wherein the variable region comprises 4 to 20 nucleotides.
16. A kit, comprising: a) a population of primers configured to amplify a whole genome or whole transcriptome, wherein the population of primers are non-self-complementary and non-complementary to other primers in the population, and comprise in a 5′ to 3′ orientation a constant region and a variable region, wherein the constant region sequence has a known sequence that is constant among a plurality of primers of the population and the variable region sequence is degenerate among the plurality of primers of the population, wherein the primers of the population have sequences that are 70% or more comprised of two non-complementary and non-self-complementary nucleotides; b) at least one target-specific primer for targeted amplification; c) at least one nested primer for further amplifying amplicons generated by the targeted amplification; and d) a set of instructions for using the kit to detect copy number variation (CNV), genotype single nucleotide polymorphism (SNP), genotype micro-satellite, detect insertion and/or deletion, determine zygosity, or detect mutation(s), wherein the sequence of the constant and variable regions will not cross-hybridize or self-hybridize under conditions described in the set of instructions.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.
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DETAILED DESCRIPTION OF THE INVENTION
(59) In keeping with long-standing patent law convention, the words “a” and “an” when used in the present specification in concert with the word comprising, including the claims, denote “one or more.”
(60) The practice of the present invention will employ, unless otherwise indicated, conventional techniques of molecular biology, microbiology, recombinant DNA, and so forth which are within the skill of the art. Such techniques are explained fully in the literature. See e.g., Sambrook, Fritsch, and Maniatis, MOLECULAR CLONING: A LABORATORY MANUAL, Second Edition (1989), OLIGONUCLEOTIDE SYNTHESIS (M. J. Gait Ed., 1984), ANIMAL CELL CULTURE (R. I. Freshney, Ed., 1987), the series METHODS IN ENZYMOLOGY (Academic Press, Inc.); GENE TRANSFER VECTORS FOR MAMMALIAN CELLS (J. M. Miller and M. P. Calos eds. 1987), HANDBOOK OF EXPERIMENTAL IMMUNOLOGY, (D. M. Weir and C. C. Blackwell, Eds.), CURRENT PROTOCOLS IN MOLECULAR BIOLOGY (F. M. Ausubel, R. Brent, R. E. Kingston, D. D. Moore, J. G. Siedman, J. A. Smith, and K. Struhl, eds., 1987), CURRENT PROTOCOLS IN IMMUNOLOGY (J. E. coligan, A. M. Kruisbeek, D. H. Margulies, E. M. Shevach and W. Strober, eds., 1991); ANNUAL REVIEW OF IMMUNOLOGY; as well as monographs in journals such as ADVANCES IN IMMUNOLOGY. All patents, patent applications, and publications mentioned herein, both supra and infra, are hereby incorporated herein by reference.
(61) U.S. Provisional Patent Application No. 60/453,071, filed Mar. 7, 2003 is hereby incorporated by reference herein in its entirety. U.S. Nonprovisional patent application Ser. No. 10/797,333 is also hereby incorporated by reference herein in its entirety. U.S. Patent Application 20030143599 is also incorporated by reference herein in its entirety.
I. Definitions
(62) The term “base analog” as used herein refers to a compound similar to one of the four DNA bases (adenine, cytosine, guanine, and thymine) but having a different composition and, as a result, different pairing properties. For example, 5-bromouracil is an analog of thymine but sometimes pairs with guanine, and 2-aminopurine is an analog of adenine but sometimes pairs with cytosine.
(63) The term “backbone analog” as used herein refers to a compound wherein the deoxyribose phosphate backbone of DNA has been modified. The modifications can be made in a number of ways to change nuclease stability or cell membrane permeability of the modified DNA. For example, peptide nucleic acid (PNA) is a new DNA derivative with an amide backbone instead of a deoxyribose phosphate backbone. Other examples in the art include methylphosphonates.
(64) The term “blocked 3′ end” as used herein is defined as a 3′ end of DNA lacking a hydroxyl group.
(65) The term “blunt end” as used herein refers to the end of a double stranded DNA molecule having 5′ and 3′ ends, wherein the 5′ and 3′ ends terminate at the same position. Thus, the blunt end comprises no 5′ or 3′ overhang.
(66) The term “complementarity” as used herein refers to the ability to form a Watson-Crick base pair through specific hydrogen bonds.
(67) The term “contig” as used herein refers to a contiguous (continuous) sequence of DNA constructed from overlapping sequences.
(68) The term “degenerate” as used herein refers to a nucleotide or series of nucleotides wherein the identity can be selected from a variety of choices of nucleotides, as opposed to a defined sequence. In specific embodiments, there can be a choice from two or more different nucleotides. In further specific embodiments, the selection of a nucleotide at one particular position comprises selection from only purines, only pyrimidines, or from non-pairing purines and pyrimidines.
(69) The term “self-inert” as used herein refers to the inability of a primer or a mixture of primers to self-prime and initiate DNA synthesis in the presence of DNA polymerase and dNTPs but in the absence of other DNA templates. It may also refer to a collective set of mRNAs in a cell.
(70) The term “DNA immortalization” as used herein refers to the conversion of a mixture of DNA molecules into a form that allows repetitive, unlimited amplification without loss of representation and/or without size reduction. In a specific embodiment, the mixture of DNA molecules comprises more than one copy of a particular DNA sequence. In another specific embodiment, the mixture of DNA molecules comprises a genome.
(71) The term “genome” as used herein is defined as the collective gene set carried by an individual, cell, or organelle.
(72) The term “genomic DNA” as used herein is defined as DNA material comprising the partial or full collective gene set carried by an individual, cell, or organelle.
(73) The term “transcriptome” as used herein is defined as the collective RNA set expressed within a cell.
(74) The term “hybridization” as used herein refers to a process of formation of double stranded DNA regions between one, two or many complementary single stranded DNA molecules. In some embodiments, however, triple stranded DNA regions are generated through hybridization.
(75) The term “minimal redundancy” as used herein refers to a minimal number of sequenced DNA fragments that produces a contig. A skilled artisan recognizes this is as opposed to “shotgun” sequencing where high redundancy is necessary to complete all gaps. Typically, the redundancy of “shotgun” sequencing is about 10-15 (where redundancy=total amount of sequenced DNA divided by the size of the genome), whereas with minimal redundancy the redundancy may be between 1 and about 2.
(76) The term “non-canonical or non-Watson-Crick base pair” as used herein refers to all possible interactions between bases that do not include standard (Watson-Crick) A-T and G-C pairing. In a specific embodiment, the non-canonical base pair comprises an adenine nucleobase and a guanine nucleobase, an adenine nucleobase and a cytosine nucleobase, a cytosine nucleobase and a thymidine nucleobase, a guanine nucleobase and a thymidine nucleobase, an adenine nucleobase and an adenine nucleobase, a guanine nucleobase and a guanine nucleobase, a cytosine nucleobase and a cytosine nucleobase, or a thymidine nucleobase and a thymidine nucleobase.
(77) The term “non-complementary” refers to nucleic acid sequence that lacks the ability to form intermolecularly at least one Watson-Crick base pair through specific hydrogen bonds.
(78) The term “non-self-complementary” refers to nucleic acid sequence that lacks the ability to form intramolecularly at least one Watson-Crick base pair through specific hydrogen bonds.
(79) The term “non strand-displacing polymerase” as used herein is defined as a polymerase that extends until it is stopped by the presence of, for example, a downstream primer. In a specific embodiment, the polymerase lacks 5′-3′exonuclease activity.
(80) The term “randomly fragmenting” as used herein refers to fragmenting a DNA molecule in a non-ordered fashion, such as irrespective of the sequence identity or position of the nucleotide comprising and/or surrounding the break. In a specific embodiment, the random fragmentation is mechanical, chemical, or enzymatic, by well-known methods in the art.
(81) The term “RNA immortalization” as used herein refers to the conversion of a mixture of RNA molecules, such as a transcriptome, into a form that allows repetitive, unlimited amplification without loss of representation and/or without size reduction. In a specific embodiment, a transcriptome is defined as a collection of transcribed mRNA molecules from a cell, an individual, or an organelle.
(82) The term “single stranded nucleic acid molecule/primer mixture” as used herein refers to a mixture comprising at least one single stranded nucleic acid molecule wherein at least one primer, as described herein, is hybridized to a region in said single stranded nucleic acid molecule. In specific embodiments, multiple degenerate primers comprise complementary sequence to at least some part of the single stranded nucleic acid molecule. In further specific embodiments, the mixture comprises a plurality of single stranded nucleic acid molecules having multiple degenerate primers hybridized thereto. In additional specific embodiments, the single stranded nucleic acid molecule is DNA or RNA.
(83) The term “strand-displacing polymerase” as used herein is defined as a polymerase that will displace downstream fragments as it extends. In a specific embodiment, the polymerase comprises 5′-3′ exonuclease activity.
(84) The term “substantially incapable” as used herein refers to a majority of polynucleotides being incapable of an activity upon subjection to standard conditions known in the art. In a specific embodiment, the activities include self-hybridization; self-priming; hybridization to another polynucleotide in the plurality; initiation of a polymerization reaction in the plurality, or a combination thereof. In a specific embodiment, the term refers to at least about 70% of a primer molecule being comprised of two noncomplementary and non-self-complementary nucleotides, more preferably at least about 75%, more preferably at least about 80%, more preferably at least about 85%, more preferably at least about 90%, more preferably at least about 95%, more preferably at least about 97%, more preferably at least about 99%, and most preferably 100% of a primer molecule being comprised of two noncomplementary and non-self-complementary nucleotides.
(85) The term “substantially non-self-complementary and substantially non-complementary” as used herein refers to a plurality of primers that lack the ability to form intramolecularly and intermolecularly a Watson-Crick base pair through specific hydrogen bonds. In a specific embodiment, at least about 70% of a primer molecule in the plurality is comprised of two noncomplementary and non-self-complementary nucleotides, more preferably at least about 75%, more preferably at least about 80%, more preferably at least about 85%, more preferably at least about 90%, more preferably at least about 95%, more preferably at least about 97%, more preferably at least about 99%, and most preferably 100% of a primer molecule in the plurality is comprised of two noncomplementary and non-self-complementary nucleotides.
(86) The term “thermophilic DNA polymerase, as used herein refers to a heat-stable DNA polymerase.
(87) A skilled artisan recognizes that there is a conventional single letter code in the art to represent a selection of nucleotides for a particular nucleotide site. For example, R refers to A or G; Y refers to C or T; M refers to A or C; K refers to G or T; S refers to C or G; W refers to A or T; H refers to A or C or T; B refers to C or G or T; V refers to A or C or G; D refers to A or G or T; and N refers to A or C or G or T. Thus, a YN primer comprises at least one, and preferably more, series of dinucleotide sets each comprising a C or a T at the first position and an A, C, G, or T at the second position. These dinucleotide sets may be repeated in the primer (and/or adaptor).
II. Preparation of DNA Libraries for Whole Genome and Whole Transcriptome Amplification by Incorporating a Known Universal Sequence Using Self-Inert Degenerate Primers
(88) In embodiments of the present invention, there is whole genome or whole transcriptome amplification comprising incorporation of known universal sequence followed by a subsequent PCR amplification step using a known universal primer complementary to at least part of the known universal sequence. In a specific embodiment, the primers for incorporating the known universal sequence comprise a degenerate region, and in further specific embodiments, the known universal sequence and the degenerate region comprise non-self-complementary nucleic acid sequence. Thus, there is significant reduction in self-hybridization and intermolecular primer hybridization compared to primers lacking non-self-complementary sequence.
(89) Formation of primer dimers is a common problem in existing methods for DNA or RNA amplification using random primers. In order to achieve efficient priming for each individual sequence, random primers must be applied at very high concentrations. The efficiency of annealing to a specific target DNA or RNA template or the entire population of template molecules is greatly reduced by the formation of primer-dimers resulting from the high primer concentrations required for efficient priming.
(90) Other problems known in the art when using random primers to amplify DNA include an inability to amplify the genome in its entirety due to locus dropout (loss), generation of short amplification products, and in some cases, the inability to amplify degraded or artificially fragmented DNA.
(91) The described invention utilizes a novel type of oligonucleotide primer comprising at least as the majority of its sequence only two types of nucleotide bases that do not participate in stable Watson-Crick pairing with each other, and thus do not self-prime. The primers comprise a constant known sequence at their 5′end and a variable degenerate nucleotide sequence located 3′ to the constant known sequence. There are four possible two-base combinations known not to participate in Watson-Crick base pairing: C-T, G-A, A-C and G-T. They suggest four different types of degenerate primers that should not form a single Watson-Crick base pair that could lead to the generation of primer-dimers in the presence of DNA polymerase and dNTPs. These primers are illustrated in
(92) For example, Y-primers have a 5′ known sequence Y.sub.U comprised of C and T bases and a degenerate region (Y).sub.10 at the 3′ end comprising ten, for example, randomly selected pyrimidine bases of C and T. R-primers have a 5′ known sequence R.sub.U comprised of G and A bases and a degenerate region (R).sub.10 at the 3′ end comprising ten, for example, randomly selected purine bases of G and A. M-primers have a 5′ known sequence M.sub.U comprised of A and C bases and a degenerate region (M).sub.10 at the 3′ end comprising ten for example, randomly selected bases of A and C. Finally, K-primers have a 5′ known sequence K.sub.U comprised of G and T bases and a degenerate region (K).sub.10 at the 3′ end comprising ten, for example, randomly selected bases of G and T. Primers of the described design will not self-prime and thus will not form primer dimers. For this reason, the term “self-inert primers” is used herein. However, they will prime at target sites containing the corresponding Watson-Crick base partners, albeit with reduced overall frequency compared to completely random primers. In specific embodiments, these primers under specific conditions are capable of forming primer dimers, but at a greatly reduced level compared to primers lacking such structure.
(93) In some embodiments, these primers are supplemented with a completely random (i.e. containing any of the four bases) short nucleotide sequence at their 3′ end. Such primers are shown on
(94) Thus, in the first step of library synthesis primers of the described design are randomly incorporated in an extension/polymerization reaction with a DNA polymerase possessing at least a limited strand-displacement activity. The resulting branching process creates DNA molecules having known (universal) self-complementary sequences at their ends. In a second step referred to as the “amplification” step, these molecules are amplified exponentially by polymerase chain reaction using Taq polymerase (or other thermostable DNA polymerase) and a single primer corresponding to at least part of the known 5′-tail of the random primers.
(95) 1. Source of Nucleic Acid
(96) Single-stranded or double-stranded nucleic acid of any source or complexity, or fragments thereof, can be used as a source material and amplified by the method described in the invention. That is, in some embodiments single stranded DNA is obtained and processed according to the methods described herein, and in other embodiments double stranded DNA is obtained and manipulated to generate ssDNA, wherein the ssDNA is subjected to the methods described herein. In a specific embodiment, dsDNA is denatured with heat, chemical treatment (such as alkaline pH), mechanical manipulation, radiation, or a combination thereof. In another specific embodiment, substantially single stranded RNA is obtained and processed according to the methods described herein. In a specific embodiment, total nucleic acid is obtained as a mixture of double stranded DNA and single stranded RNA molecules and then processed to selectively amplify the DNA fraction or RNA fraction only, or both separately, or both in a mixture.
(97) 2. Design of Degenerate Primers
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(99) The choice of primers will depend on the base composition, complexity, and the presence and abundance of repetitive elements in the target DNA or RNA. By combining the products of individual amplification reactions with degenerate primers comprising different non-Watson-Crick pairs, but having the same known sequence at the ends, one can achieve the highest possible level of representative and uniform DNA amplification. A skilled artisan recognizes how to select the optimal primers and reaction conditions to achieve the desired result.
(100) Example 2 describes a comparison of different pyrimidine-only primers in their ability to form primer-dimers, efficiency of amplification, and uniformity (representation of randomly selected genomic markers) in a human whole genome amplification reaction with Klenow fragment of DNA Polymerase I. Of all pyrimidine-only primers tested, primers with two random 3′ bases (Y(N).sub.2) result in the most uniform whole genome amplification and at the same time form undetectable amounts of primer dimers. Thus, in a preferred embodiment degenerate primers comprising between about 1 and about 3 completely random bases at their 3′ end are utilized.
(101) 3. Choice of DNA Polymerases
(102) In a preferred embodiment, a DNA polymerase is utilized that possesses strand-displacement activity. Preferred strand-displacement DNA polymerases are: Klenow fragment of E. coli DNA polymerase I, exo− DNA polymerases of the T7 family, i.e. polymerases that require host thioredoxin subunit as co-factor, such as: T7, T3, fI, fII, W31, H, Y, gh-1, SP6, or All22, Studier (1979), exo− Bst large fragment, Bca DNA polymerase, 9° Nm polymerase, MMLV Reverse Transcriptase, AMV Reverse Transcriptase, HIV Reverse Transcriptase, phage f29 polymerase, phage M2 polymerase, phage fPRD1 polymerase, exo− VENT polymerase, and phage T5 exo− DNA polymerase.
(103) Klenow exo− fragment of DNA Polymerase I, phage T7 DNA polymerase with reduced or eliminated 3′-5′ exonuclease activities, and MMLV Reverse Transcriptase are most preferred in the present invention. Thus, in a preferred embodiment the Klenow exo− fragment of DNA Polymerase I, or Sequenase version 2 is used as the polymerase for whole genome amplification (Example 2), and MMLV reverse transcriptase is used as the polymerase for whole transcriptome amplification (Example 14).
(104) 4. Reaction Conditions
(105) In general, factors increasing priming efficiency, such as reduced temperature or elevated salt and/or Mg.sup.2+ ion concentration, inhibit the strand-displacement activity and the rate of DNA polymerases, and elevated temperatures and low Mg.sup.2+ ion or salt concentrations increase the efficiency of polymerization/strand-displacement but reduce the priming efficiency. On the other hand, factors promoting efficient priming also increase the chances of primer-dimer formation. Strand-displacement activity can be facilitated by several protein factors. Any polymerase that can perform strand-displacement replication, in the presence or in the absence of such strand-displacement or processivity enhancing factors, is suitable for use in the disclosed invention, even if the polymerase does not perform strand-displacement replication in the absence of such factor. Factors useful in strand-displacement replication are (i) any of a number of single-stranded DNA binding proteins (SSB proteins) of bacterial, viral, or eukaryotic origin, such as SSB protein of E. coli, phage T4 gene 32 product, phage T7 gene 2.5 protein, phage Pf3 SSB, replication protein A RPA32 and RPA14 subunits (Wold, 1997); (ii) other DNA binding proteins, such as adenovirus DNA-binding protein, herpes simplex protein ICP8, BMRF1 polymerase accessory subunit, herpes virus UL29 SSB-like protein; (iii) any of a number of replication complex proteins known to participate in DNA replication such as phage T7 helicase/primase, phage T4 gene 41 helicase, E. coli Rep helicase, E. coli recBCD helicase, E. coli and eukaryotic topoisomerases (Champoux, 2001).
(106) The exact parameters of the polymerization reaction will depend on the choice of polymerase and degenerate primers and a skilled artisan recognizes based on the teachings provided herein how to modify such parameters. By varying the number of random bases at the 3′ end of the degenerate primers and by carefully optimizing the reaction conditions, formation of primer-dimers can be kept to a minimum and at the same time the amplification efficiency and representation can be maximized.
(107) Random fragmentation of DNA, and if necessary, RNA can be performed by mechanical, chemical, or enzymatic treatment as described. In a preferred embodiment, DNA is fragmented by heating at about 95° C. in low salt buffers such as TE (10 mM Tris-HCl, 1 mM EDTA, having pH between 7.5 and 8.5) or TE-L (10 mM Tris-HCl, 0.1 mM EDTA, having pH between 7.5 and 8.5) for between about 1 min and about 10 min (for example, see U.S. patent application Ser. No. 10/293,048, filed Nov. 13, 2002, incorporated by reference herein in its entirety).
(108) An exemplary library synthesis reaction of the present invention is performed in a mixture having volume ranging between about 10 and about 25 μl. The reaction mixture preferably comprises about 0.5 to about 100 ng of thermally or mechanically fragmented DNA, or in particular embodiments less than about 0.5 ng DNA, about 0.5-about 30 μM of self-inert degenerate primer, about 0-about 200 nM of known sequence primer (i.e., primer corresponding to the known 5′ end of the respective degenerate primer), between about 2 and about 10 units of Klenow Exo.sup.− (New England Biolabs) or Sequenase version 2 (USB Corporation), between 0-about 360 ng SSB protein, and between about 5-about 10 mM MgCl.sub.2, and between 0 and about 100 mM NaCl. The reaction buffer preferably has a buffering capacity that is operative at physiological pH between about 6.5 and about 9. Preferably, the incubation time of the reaction is between about 10-about 180 min, and the incubation temperature between about 12° C. and about 37° C. Incubation is performed by cycling between about 12° C. and about 37° C. for a total of 3 to 5 min per cycle, or preferably by a single isothermal step between about 12° C. and about 30° C. or sequential isothermal steps between about 12° C. and about 37° C. The reaction is terminated by addition of a sufficient amount of EDTA to chelate Mg.sup.2+ or preferably by heat-inactivation of the polymerase, or both.
(109) In a preferred embodiment of the present invention, the library synthesis reaction is performed in a volume of about 15 μl. The reaction mixture comprises about 5 ng or less of thermally or mechanically fragmented DNA, for example, about 2 μM of self-inert degenerate primer K(N).sub.2 comprising G and T bases at the known and degenerate regions and 2 completely random 3′ bases, (Table III, primer #14), between about 2 units and about 4 units of Sequenase version 2 DNA polymerase (USB Corporation), between about 5 mM and about 10 mM MgCl.sub.2, about 100 mM NaCl, about 10 mM Tris-HCl buffer having pH of about 7.5, and about 7.5 mM dithiothreitol. Preferably, the incubation time of the reaction is between about 60 min and about 120 min and the incubation temperature is about 24° C. in an isothermal mode or in another preferred embodiment by sequential isothermal steps at between about 16° C. and about 37° C.
(110) In another preferred embodiment of the present invention, the library synthesis reaction is performed in a volume of about 20 μl. The reaction mixture comprises about 25 ng or less of thermally or fragmented or unfragmented RNA, for example, about 1 μM of self-inert degenerate primer K(N).sub.2 comprising G and T bases at the known and degenerate regions and 2 completely random 3′ bases, (Table III, primer #14), about 200 nM of a primer K(T).sub.20 comprising G and T bases at the 5′ known and poly T bases at the 3′ end (Table III, primer #19) between about 50 units and about 200 units of MMLV Reverse transcriptase (Epicentre Corporation), between about 3 mM and about 10 mM MgCl.sub.2, about 75 mM KCl, about 50 mM Tris-HCl buffer having pH of about 8.3, and about 10 mM dithiothreitol. Preferably, the incubation time of the reaction is between about 30 min and about 120 min and the incubation temperature is about 42° C. in an isothermal mode or in another preferred embodiment by sequential isothermal steps at between about 24° C. and about 42° C.
(111) A typical amplification step with known sequence primer comprises between about 1 and about 10 ng of library synthesis products and between about 0.3 and about 2 μM of known sequence primer in a standard PCR reaction well known in the art, under conditions optimal for thermostable DNA polymerases, such as Taq DNA polymerase, Pfu polymerase, or derivatives and mixtures thereof. For sequences known to be difficult to amplify, such as those high in G/C content that are known otherwise to benefit from PCR optimization efforts such as temperature and time of denaturation and polymerization steps, reaction additives such as DMSO and/or 7-Deaza dGTP may also improve representation in libraries constructed by the method of the invention.
III. Nucleic Acids
(112) The term “nucleic acid” or “polynucleotide” will generally refer to at least one molecule or strand of DNA, RNA, DNA-RNA chimera or a derivative or analog thereof, comprising at least one nucleobase, such as, for example, a naturally occurring purine or pyrimidine base found in DNA (e.g. adenine “A,” guanine “G,” thymine “T” and cytosine “C”) or RNA (e.g. A, G, uracil “U” and C). The term “nucleic acid” encompasses the terms “oligonucleotide” and “polynucleotide.” The term “oligonucleotide” refers to at least one molecule of between about 3 and about 100 nucleobases in length. The term “polynucleotide” refers to at least one molecule of greater than about 100 nucleobases in length. These definitions generally refer to at least one single-stranded molecule, but in specific embodiments will also encompass at least one additional strand that is partially, substantially, or fully complementary to at least one single-stranded molecule. Thus, a nucleic acid may encompass at least one double-stranded molecule or at least one triple-stranded molecule that comprises one or more complementary strand(s) or “complement(s)” of a particular sequence comprising a strand of the molecule. As used herein, a single stranded nucleic acid may be denoted by the prefix “ss”, a double stranded nucleic acid by the prefix “ds”, and a triple stranded nucleic acid by the prefix “ts.”
(113) Nucleic acid(s) that are “complementary” or “complement(s)” are those that are capable of base-pairing according to the standard Watson-Crick, Hoogsteen or reverse Hoogsteen binding complementarity rules. However, in a specific embodiment, a primer of the present invention comprises a majority of nucleotides that are incapable of forming standard Watson-Crick base pairs, particularly with other nucleotides within the same primer.
(114) As used herein, the term “complementary” or “complement(s)” may refer to nucleic acid(s) that are substantially complementary, as may be assessed by the same nucleotide comparison set forth above. The term “substantially complementary” may refer to a nucleic acid comprising at least one sequence of consecutive nucleobases, or semiconsecutive nucleobases if one or more nucleobase moieties are not present in the molecule, are capable of hybridizing to at least one nucleic acid strand or duplex even if less than all nucleobases do not base pair with a counterpart nucleobase. In certain embodiments, a “substantially complementary” nucleic acid contains at least one sequence in which about 70%, about 71%, about 72%, about 73%, about 74%, about 75%, about 76%, about 77%, about 77%, about 78%, about 79%, about 80%, about 81%, about 82%, about 83%, about 84%, about 85%, about 86%, about 87%, about 88%, about 89%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, to about 100%, and any range therein, of the nucleobase sequence is capable of base-pairing with at least one single or double stranded nucleic acid molecule during hybridization. In certain embodiments, the term “substantially complementary” refers to at least one nucleic acid that may hybridize to at least one nucleic acid strand or duplex in stringent conditions. In certain embodiments, a “partially complementary” nucleic acid comprises at least one sequence that may hybridize in low stringency conditions to at least one single or double stranded nucleic acid, or contains at least one sequence in which less than about 70% of the nucleobase sequence is capable of base-pairing with at least one single or double stranded nucleic acid molecule during hybridization.
(115) As used herein, “hybridization”, “hybridizes” or “capable of hybridizing” is understood to mean the forming of a double or triple stranded molecule or a molecule with partial double or triple stranded nature. The term “hybridization”, “hybridize(s)” or “capable of hybridizing” encompasses the terms “stringent condition(s)” or “high stringency” and the terms “low stringency” or “low stringency condition(s).”
(116) As used herein “stringent condition(s)” or “high stringency” are those that allow hybridization between or within one or more nucleic acid strand(s) containing complementary sequence(s), but precludes hybridization of random sequences. Stringent conditions tolerate little, if any, mismatch between a nucleic acid and a target strand. Such conditions are well known to those of ordinary skill in the art, and are preferred for applications requiring high selectivity. Non-limiting applications include isolating at least one nucleic acid, such as a gene or nucleic acid segment thereof, or detecting at least one specific mRNA transcript or nucleic acid segment thereof, and the like.
(117) Stringent conditions may comprise low salt and/or high temperature conditions, such as provided by about 0.02 M to about 0.15 M NaCl at temperatures of about 50° C. to about 70° C. It is understood that the temperature and ionic strength of a desired stringency are determined in part by the length of the particular nucleic acid(s), the length and nucleobase content of the target sequence(s), the charge composition of the nucleic acid(s), and to the presence of formamide, tetramethylammonium chloride or other solvent(s) in the hybridization mixture. It is generally appreciated that conditions may be rendered more stringent, such as, for example, the addition of increasing amounts of formamide.
(118) It is also understood that these ranges, compositions and conditions for hybridization are mentioned by way of non-limiting example only, and that the desired stringency for a particular hybridization reaction is often determined empirically by comparison to one or more positive or negative controls. Depending on the application envisioned, it is preferred to employ varying conditions of hybridization to achieve varying degrees of selectivity of the nucleic acid(s) towards target sequence(s). In a non-limiting example, identification or isolation of related target nucleic acid(s) that do not hybridize to a nucleic acid under stringent conditions may be achieved by hybridization at low temperature and/or high ionic strength. Such conditions are termed “low stringency” or “low stringency conditions”, and non-limiting examples of low stringency include hybridization performed at about 0.15 M to about 0.9 M NaCl at a temperature range of about 20° C. to about 50° C. Of course, it is within the skill of one in the art to further modify the low or high stringency conditions to suite a particular application.
(119) As used herein a “nucleobase” refers to a naturally occurring heterocyclic base, such as A, T, G, C or U (“naturally occurring nucleobase(s)”), found in at least one naturally occurring nucleic acid (i.e. DNA and RNA), and their naturally or non-naturally occurring chimeras, derivatives, and analogs. Non-limiting examples of nucleobases include purines and pyrimidines, as well as derivatives and analogs thereof, which generally can form one or more hydrogen bonds (“anneal” or “hybridize”) with at least one naturally occurring nucleobase in a manner that may substitute for naturally occurring nucleobase pairing (e.g. the hydrogen bonding between A and T, G and C, and A and U).
(120) As used herein, a “nucleotide” refers to a nucleoside further comprising a “backbone moiety” generally used for the covalent attachment of one or more nucleotides to another molecule or to each other to form one or more nucleic acids. The “backbone moiety” in naturally occurring nucleotides typically comprises a phosphorus moiety, which is covalently attached to a 5-carbon sugar. The attachment of the backbone moiety typically occurs at either the 3′- or 5′-position of the 5-carbon sugar. However, other types of attachments are known in the art, particularly when the nucleotide comprises derivatives or mimics of a naturally occurring 5-carbon sugar or phosphorus moiety, and non-limiting examples are described herein.
IV. Amplification of Nucleic Acids
(121) Nucleic acids useful as templates for amplification are generated by methods described herein. In a specific embodiment, the DNA molecule from which the methods generate the nucleic acids for amplification may be isolated from cells, tissues or other samples according to standard methodologies (Sambrook et al., 1989).
(122) The term “primer,” as used herein, is meant to encompass any nucleic acid that is capable of priming the synthesis of a nascent nucleic acid in a template-dependent process. Typically, primers are oligonucleotides from ten to twenty and/or thirty base pairs in length, but longer sequences can be employed. Primers may be provided in double-stranded and/or single-stranded form, although the single-stranded form is preferred.
(123) Pairs of primers designed to selectively hybridize to nucleic acids are contacted with the template nucleic acid under conditions that permit selective hybridization. Depending upon the desired application, high stringency hybridization conditions may be selected that will only allow hybridization to sequences that are completely complementary to the primers. In other embodiments, hybridization may occur under reduced stringency to allow for amplification of nucleic acids containing one or more mismatches with the primer sequences. Once hybridized, the template-primer complex is contacted with one or more enzymes that facilitate template-dependent nucleic acid synthesis. Multiple rounds of amplification, also referred to as “cycles,” are conducted until a sufficient amount of amplification product is produced.
(124) The amplification product may be detected or quantified. In certain applications, the detection may be performed by visual means. Alternatively, the detection may involve indirect identification of the product via chemiluminescence, radioactive scintigraphy of incorporated radiolabel or fluorescent label or even via a system using electrical and/or thermal impulse signals (Affymax technology).
(125) A number of template dependent processes are available to amplify the oligonucleotide sequences present in a given template sample. One of the best known amplification methods is the polymerase chain reaction (referred to as PCR™) which is described in detail in U.S. Pat. Nos. 4,683,195, 4,683,202 and 4,800,159, and in Innis et al., 1990, each of which is incorporated herein by reference in their entirety. Briefly, two synthetic oligonucleotide primers, which are complementary to two regions of the template DNA (one for each strand) to be amplified, are added to the template DNA (that need not be pure), in the presence of excess deoxynucleotides (dNTP's) and a thermostable polymerase, such as, for example, Taq (Thermus aquaticus) DNA polymerase. In a series (typically 30-35) of temperature cycles, the target DNA is repeatedly denatured (around 95° C.), annealed to the primers (typically at 50-60° C.) and a daughter strand extended from the primers (72° C.). As the daughter strands are created they act as templates in subsequent cycles. Thus, the template region between the two primers is amplified exponentially, rather than linearly.
(126) A reverse transcriptase PCR™ amplification procedure may be performed to quantify the amount of mRNA amplified. Methods of reverse transcribing RNA into cDNA are well known and described in Sambrook et al., 1989. Alternative methods for reverse transcription utilize thermostable DNA polymerases. These methods are described in WO 90/07641. Polymerase chain reaction methodologies are well known in the art. Representative methods of RT-PCR™ are described in U.S. Pat. No. 5,882,864.
(127) A. LCR
(128) Another method for amplification is the ligase chain reaction (“LCR”), disclosed in European Patent Application No. 320,308, incorporated herein by reference. In LCR, two complementary probe pairs are prepared, and in the presence of the target sequence, each pair will bind to opposite complementary strands of the target such that they abut. In the presence of a ligase, the two probe pairs will link to form a single unit. By temperature cycling, as in PCR™, bound ligated units dissociate from the target and then serve as “target sequences” for ligation of excess probe pairs. U.S. Pat. No. 4,883,750, incorporated herein by reference, describes a method similar to LCR for binding probe pairs to a target sequence.
(129) B. Qbeta Replicase
(130) Qbeta Replicase, described in PCT Patent Application No. PCT/US87/00880, also may be used as still another amplification method in the present invention. In this method, a replicative sequence of RNA which has a region complementary to that of a target is added to a sample in the presence of an RNA polymerase. The polymerase will copy the replicative sequence which can then be detected and quantified
(131) C. Isothermal Amplification
(132) An isothermal amplification method, in which restriction endonucleases and ligases are used to achieve the amplification of target molecules that contain nucleotide thiophosphates in one strand of a restriction site also may be useful in the amplification of nucleic acids in the present invention. Such an amplification method is described by Walker et al. 1992, incorporated herein by reference.
(133) D. Strand Displacement Amplification
(134) Strand Displacement Amplification (SDA) is another method of carrying out isothermal amplification of nucleic acids which involves multiple rounds of strand displacement and synthesis, i.e., nick translation. A similar method, called Repair Chain Reaction (RCR), involves annealing several probes throughout a region targeted for amplification, followed by a repair reaction in which only two of the four bases are present. The other two bases can be added as biotinylated derivatives for easy detection. A similar approach is used in SDA.
(135) E. Cyclic Probe Reaction
(136) Target specific sequences can also be detected using a cyclic probe reaction (CPR). In CPR, a probe having 3′ and 5′ sequences of non-specific DNA and a middle sequence of specific RNA is hybridized to DNA which is present in a sample. Upon hybridization, the reaction is treated with RNase H, and the products of the probe identified as distinctive products which are released after digestion. The original template is annealed to another cycling probe and the reaction is repeated.
(137) F. Transcription-Based Amplification
(138) Other nucleic acid amplification procedures include transcription-based amplification systems (TAS), including nucleic acid sequence based amplification (NASBA) and 3SR, Kwoh et al., 1989; PCT Patent Application WO 88/10315, each incorporated herein by reference).
(139) In NASBA, the nucleic acids can be prepared for amplification by standard phenol/chloroform extraction, heat denaturation of a clinical sample, treatment with lysis buffer and minispin columns for isolation of DNA and RNA or guanidinium chloride extraction of RNA. These amplification techniques involve annealing a primer which has target specific sequences. Following polymerization, DNA/RNA hybrids are digested with RNase H while double stranded DNA molecules are heat denatured again. In either case the single stranded DNA is made fully double stranded by addition of a second target specific primer, followed by polymerization. The double-stranded DNA molecules are then multiply transcribed by an RNA polymerase, such as T7 or SP6. In an isothermal cyclic reaction, the RNAs are reverse transcribed into double stranded DNA, and transcribed once again with an RNA polymerase, such as T7 or SP6. The resulting products, whether truncated or complete, indicate target specific sequences.
(140) G. Rolling Circle Amplification
(141) Rolling circle amplification (U.S. Pat. No. 5,648,245) is a method to increase the effectiveness of the strand displacement reaction by using a circular template. The polymerase, which does not have a 5′ exonuclease activity, makes multiple copies of the information on the circular template as it makes multiple continuous cycles around the template. The length of the product is very large—typically too large to be directly sequenced. Additional amplification is achieved if a second strand displacement primer is added to the reaction using the first strand displacement product as a template.
(142) H. Other Amplification Methods
(143) Other amplification methods, as described in British Patent Application No. GB 2,202,328, and in PCT Patent Application No. PCT/US89/01025, each incorporated herein by reference, may be used in accordance with the present invention. In the former application, “modified” primers are used in a PCR™ like, template and enzyme dependent synthesis. The primers may be modified by labeling with a capture moiety (e.g., biotin) and/or a detector moiety (e.g., enzyme). In the latter application, an excess of labeled probes are added to a sample. In the presence of the target sequence, the probe binds and is cleaved catalytically. After cleavage, the target sequence is released intact to be bound by excess probe. Cleavage of the labeled probe signals the presence of the target sequence.
(144) Miller et al., PCT Patent Application WO 89/06700 (incorporated herein by reference) disclose a nucleic acid sequence amplification scheme based on the hybridization of a promoter/primer sequence to a target single-stranded DNA (“ssDNA”) followed by transcription of many RNA copies of the sequence. This scheme is not cyclic, i.e., new templates are not produced from the resultant RNA transcripts.
(145) Other suitable amplification methods include “RACE” and “one-sided PCR™” (Frohman, 1990; Ohara et al., 1989, each herein incorporated by reference). Methods based on ligation of two (or more) oligonucleotides in the presence of nucleic acid having the sequence of the resulting “di-oligonucleotide”, thereby amplifying the di-oligonucleotide, also may be used in the amplification step of the present invention, Wu et al., 1989, incorporated herein by reference).
V. Enzymes
(146) Enzymes that may be used in conjunction with the invention include nucleic acid modifying enzymes listed in the following tables.
(147) TABLE-US-00001 TABLE I POLYMERASES AND REVERSE TRANSCRIPTASES Thermostable DNA Polymerases: OmniBase ™ Sequencing Enzyme Pfu DNA Polymerase Taq DNA Polymerase Taq DNA Polymerase, Sequencing Grade TaqBead ™ Hot Start Polymerase AmpliTaq Gold Tfl DNA Polymerase Tli DNA Polymerase Tth DNA Polymerase DNA Polymerases: DNA Polymerase I, Klenow Fragment, Exonuclease Minus DNA Polymerase I DNA Polymerase I Large (Klenow) Fragment Terminal Deoxynucleotidyl Transferase T4 DNA Polymerase Reverse Transcriptases: AMV Reverse Transcriptase MMLV Reverse Transcriptase HIV Reverse Transcriptase
(148) TABLE-US-00002 TABLE II DNA/RNA MODIFYING ENZYMES Ligases: T4 DNA Ligase Kinases T4 Polynucleotide Kinase
VI. DNA Polymerases
(149) In a preferred embodiment, a DNA polymerase is used in methods of the present invention. In some embodiments, it is envisioned that the methods of the invention could be carried out with one or more enzymes where multiple enzymes combine to carry out the function of a single DNA polymerase molecule retaining 5′-3′ exonuclease activities. Effective polymerases that retain 5′-3′ exonuclease activity include, for example, E. coli DNA polymerase I, Taq DNA polymerase, S. pneumoniae DNA polymerase I, Tfl DNA polymerase, D. radiodurans DNA polymerase I, Tth DNA polymerase, Tth XL DNA polymerase, M. tuberculosis DNA polymerase I, M. thermoautotrophicum DNA polymerase I, Herpes simplex-1 DNA polymerase, E. coli DNA polymerase I Klenow fragment, Vent DNA polymerase, thermosequenase and wild-type or modified T7 DNA polymerases. In preferred embodiments, the effective polymerase is E. coli DNA polymerase I, Klenow, or Taq DNA polymerase, or MMLV reverse transcriptase.
(150) Where a break in the substantially double stranded nucleic acid template is a gap of at least a base or nucleotide in length that comprises, or is reacted to comprise, a 3′ hydroxyl group, the range of effective polymerases that may be used is even broader. In such aspects, the effective polymerase may be, for example, E. coli DNA polymerase I, Taq DNA polymerase, S. pneumoniae DNA polymerase I, Tfl DNA polymerase, D. radiodurans DNA polymerase I, Tth DNA polymerase, Tth XL DNA polymerase, M. tuberculosis DNA polymerase I, M. thermoautotrophicum DNA polymerase I, Herpes simplex-1 DNA polymerase, E. coli DNA polymerase I Klenow fragment, T4 DNA polymerase, Vent DNA polymerase, thermosequenase or a wild-type or modified T7 DNA polymerase. In preferred aspects, the effective polymerase is E. coli DNA polymerase I, M. tuberculosis DNA polymerase I, Taq DNA polymerase, or T4 DNA polymerase.
VII. Hybridization
(151) Depending on the application envisioned, one would desire to employ varying conditions of hybridization to achieve varying degrees of selectivity of the probe or primers for the target sequence, such as in the adaptor. For applications requiring high selectivity, one will typically desire to employ relatively high stringency conditions to form the hybrids. For example, relatively low salt and/or high temperature conditions, such as provided by about 0.02 M to about 0.10 M NaCl at temperatures of about 50° C. to about 70° C. Such high stringency conditions tolerate little, if any, mismatch between the probe or primers and the template or target strand and would be particularly suitable for isolating specific genes or for detecting specific mRNA transcripts. It is generally appreciated that conditions can be rendered more stringent by the addition of increasing amounts of formamide.
(152) Conditions may be rendered less stringent by increasing salt concentration and/or decreasing temperature. For example, a medium stringency condition could be provided by about 0.1 to 0.25 M NaCl at temperatures of about 37° C. to about 55° C., while a low stringency condition could be provided by about 0.15 M to about 0.9 M salt, at temperatures ranging from about 20° C. to about 55° C. Hybridization conditions can be readily manipulated depending on the desired results.
(153) In other embodiments, hybridization may be achieved under conditions of, for example, 50 mM Tris-HCl (pH 8.3), 75 mM KCl, 35 mM MgCl.sub.2, 1.0 mM dithiothreitol, at temperatures between approximately 20° C. to about 37° C. Other hybridization conditions utilized could include approximately 10 mM Tris-HCl (pH 8.3), 50 mM KCl, 1.5 mM MgCl.sub.2, at temperatures ranging from approximately 40° C. to about 72° C.
EXAMPLES
(154) The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples that follow represent techniques discovered by the inventors to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.
Example 1: Design of Degenerate Pyrimidine Primers and Analysis of Self-Priming and Extension
(155) Pyrimidine primers comprising a constant 18 base sequence, followed by 10 random pyrimidines and between 0 and 6 completely random bases at the 3′ end (Table III, primers 1-7), are compared for their ability to self prime and to extend a model template oligonucleotide.
(156) TABLE-US-00003 TABLE III OLIGONUCLEOTIDE SEQUENCES No Code Sequence 5′-3′ * 1. Y CCTTTCTCTCCCTTCTCTYYYYYYYYYY (SEQ ID NO: 11) 2. YN CCTTTCTCTCCCTTCTCTYYYYYYYYYYN (SEQ ID NO: 12) 3. Y(N).sub.2 CCTTTCTCTCCCTTCTCTYYYYYYYYYYNN (SEQ ID NO: 13) 4. Y(N).sub.3 CCTTTCTCTCCCTTCTCTYYYYYYYYYYNNN (SEQ ID NO: 14) 5. Y(N).sub.4 CCTTTCTCTCCCTTCTCTYYYYYYYYYNNNN (SEQ ID NO: 15) 6. Y(N).sub.5 CCTTTCTCTCCCTTCTCTYYYYYYYYYYNNNNN (SEQ ID NO: 16) 7. Y(N).sub.6 CCTTTCTCTCCCTTCTCTYYYYYYYYYYNNNNNN (SEQ ID NO: 17) 8 Y.sub.U CCTTTCTCTCCCTTCTCT (SEQ ID NO: 18) 9. Template GTAATACGACTCACTATAGGRRRRRRRRRR (SEQ ID NO: 19) 10. R(N).sub.2 AGAGAAGGGAGAGAAAGGRRRRRRRRRRNN (SEQ ID NO: 20) 11. R.sub.U AGAGAAGGGAGAGAAAGG (SEQ ID NO: 21) 12. M(N).sub.2 CCAAACACACCCAACACAMMMMMMMMMMNN (SEQ ID NO: 22) 13. M.sub.U CCAAACACACCCAACACA (SEQ ID NO: 23) 14. K(N).sub.2 TGTGTTGGGTGTGTTTGGKKKKKKKKKKNN (SEQ ID NO: 24) 15. K TGTGTTGGGTGTGTTTGGKKKKKKKKKK (SEQ ID NO: 25) 16. K.sub.U TGTGTTGGGTGTGTTTGG (SEQ ID NO: 26) 17 T7(N).sub.6 GTAATACGACTCACTATAGGNNNNNN (SEQ ID NO: 27) 18. T7 GTAATACGACTCACTATAGG (SEQ ID NO: 28) 19. K(T20) TGTGTTGGGTGTGTTTGGTTTTTTTTTTTTTTTTTTTT (SEQ ID NO: 29) * Random bases definitions: Y = C or T; R = A or G; M = A or C; K = G or T
(157) The model template oligonucleotide (Table III, Oligonucleotide 9) was comprised of T7 promoter sequence followed by 10 random purine bases at its 3′-terminus. The reaction mixture contained 1× ThermoPol reaction buffer (NEB), 4 units of Bst DNA Polymerase Large Fragment (NEB), 200 uM dNTPS, 350 nM template oligo 9, and 3.5 or 35 μM of degenerate pyrimidine primers Y and YN (Table III, primers 1 to 7) in a final volume of 25 Controls comprising no dNTPs are also included for each Y or YN primer. Samples were incubated for 5 min or 15 min at 45° C. and stopped by adding 2 μl of 0.5 M EDTA. Aliquots of the reactions were analyzed on 10% TB-urea denaturing polyacrylamide gels (Invitrogen) after staining with SybrGold dye (Molecular Probes).
Example 2: Comparison of Different Degenerate Pyrimidine Primers Used in the Library Synthesis with Klenow Exo− Fragment of DNA Polymerase-I and Subsequent Whole Genome Amplification
(158) Human lymphocyte genomic DNA isolated by standard procedures was randomly fragmented in TE buffer to an average size of 1.5 Kb using the Hydro Shear™ device (Gene Machines; Palo Alto, Calif.). The reaction mixture contained 50 ng of fragmented DNA in 1× EcoPol buffer (NEB), 200 μM of each dNTP, 360 ng of Single Stranded DNA Binding Protein (USB), 500 nM of known Y.sub.U primer (Table III, primer 8), and 1 μM of degenerate pyrimidine primers with 0 to 6 random 3′ bases (Table III, primers 1-7) or 1 μM of T7 primer with six random N bases at the 3′ end (Table III, T7(N).sub.6 primer 16,) in a final volume of 25 μl. After a denaturing step of 2 min at 95° C., the samples were cooled to 16° C., and the reaction was initiated by adding 5 units of Klenow enzyme that lacks 3′-5′ exonuclease activity (NEB). WGA library synthesis was carried out in a three-step protocol for 10 min at 16° C., 10 min at 24° C., and 15 min at 37° C. Reactions were stopped with 1 μl of 250 mM EDTA (pH 8.0), and samples were heated for 3 min at 95° C. Aliquots were analyzed on a 1% agarose gel after staining with EtBr (
(159) Aliquots of the library reactions corresponding to 5 ng of input DNA were further amplified by real-time PCR. The PCR reaction mixture contained: 1× Titanium Taq reaction buffer (Clontech), 200 μM each dNTP, 100,000× dilutions of fluorescein and SybrGold I (Molecular Probes), 1 μM known Y.sub.U primer (or in the case of degenerate T7(N).sub.6 primers, known primer T7 (Table III, primer 17), 5 units of Titanium Taq polymerase (Clontech), and 3 μl aliquots (approximately 5 ng input genomic DNA) of the Klenow library synthesis reactions in a final volume of 50 μl. Reactions were carried out for 18 cycles at 94° C. for 15 sec and 65° C. for 2 min on I-Cycler™ real-time PCR instruments (Bio-Rad).
(160) Representation analysis of the samples prepared with pyrimidine primers with 0 to 6 random 3′ bases was conducted using a panel of 30 human genomic STS markers (Table IV, STS markers 1-6, 8-10, 12, 14, 16, 19, 20, 23, 26, 29-31, 35, 36, 38, 40, 41, 43, 44, 46, 47, and 49)
(161) TABLE-US-00004 TABLE IV EXEMPLARY HUMAN STS MARKERS USED FOR REPRESENTATION ANALYSIS BY QUANTITATIVE REAL-TIME PCR No * UniSTS Database Name** 1 RH18158 2 SHGC-100484 3 SHGC-82883 4 SHGC-149956 5 SHGC-146783 6 SHGC-102934 8 csnpmnat1-pcr1-1 9 stSG62224 10 SHGC-142305 12 SHGC-80958 13 SHGC-74059 14 SHGC-83724 16 SHGC-145896 19 SHGC-155401 20 csnpharp-pcr2-3 22 stb39J12.sp6 23 SHGC-149127 26 949_F_8Left 29 SHGC-148759 30 SHGC-154046 31 WI-19180 35 SHGC-146602 36 SHGC-130262 38 SHGC-130314 40 SHGC-147491 41 stSG53466 42 SHGC-105883 42a GDB:533006 42b D19S1101 43 SHGC-79237 44 SHGC-153761 46 stSG50529 47 SHGC-132199 49 stSG49452 51 SGC32543 52 SHGC-2457 53 stSG53950 54 stSG43297 55 SHGC-81536 58 stSG48086 60 stSG62388 62 stSG50542 63 stSG44393 66 SHGC-9458 67 SHGC-5506 68 SHGC-153324 69 stSG53179 70 sts-X16316 71 stSG51782 72 stSG48421 74 stGDB:442878 76 WI-6290 77 T94852 79 SHGC-11640 80 H58497 81 stSG34953 82 KIAA0108 83 Y00805 84 sts-W93373 85 stSG45551 85a Cda0ge01 85b RH18026 86 U34806 88 SHGC-12728 89 SHGC-10570 91 stSG52141 92 SHGC-58853 94 SHGC-36464 96 stSG8946 97 SHGC-10187 99 WI-13668 103 stSG49584 104 M55047 105 SHGC-102231 106 stSG60168 107 stSG50880 108 stSG39197 110 sts-AA035504 111 SGC35140 113 stSG53011 114 sts-R44709 116 SHGC-149512 117 stSG55021 118 SHGC-79529 119 KIAA0181 119a GDB:314031 119b RH28558 120 SHGC-105119 121 SHGC-79242 122 SHGC-170363 123 stSG50637 126 RH69540 130 GDB:181552 133 1770 134 1314 135 SHGC-104164 136 SHGC-101034 137 stSG62239 138 stSG60144 139 stSG58407 140 stSG58405 141 sts-T50718 144 SHGC-17057 145 sts-N90764 152 SHGC-132991 154 SHGC-57595 Alu Yb8 * Omitted sequential numbers indicate dropped STS sequences that did not amplify well in quantitative RT-PCR **Unique names of STS marker sequences are from the National Center for Biotechnology Information UniSTS database. Sequences of the STS regions as well as the forward and backward primers used in quantitative real-time PCR can be found in the UniSTS database at the National Center for Biotechnology Information's website.
(162) The material amplified by PCR with the known Y.sub.U primer was purified with Qiaquick filters (Qiagen), and 10 ng aliquots were analyzed in real-time PCR. Reactions were carried out for 45 cycles at 94° C. for 15 sec and 68° C. for 1 min on an I-Cycler (Bio-Rad), as described above, in a 25 μl volume. Standards corresponding to 10, 1, and 0.2 ng of fragmented DNA were used for each STS, quantities were calculated by standard curve fit for each STS (I-Cycler software, Bio-Rad) and were plotted as frequency histograms (
Example 3: Whole Genome Amplification of Thermally Fragmented Genomic DNA Converted into an Amplifiable DNA Library Using Klenow Exo− Fragment of DNA Polymerase-I or Sequenase Version-2 and Degenerate Primers Y(N).SUB.2
(163) Human lymphocyte genomic DNA isolated by standard procedures was randomly fragmented in TE-L buffer (10 mM Tris, 0.1 mM EDTA, pH 7.5) by heating at 95° C. for 5 min. The reaction mixture contained 100 ng of thermally fragmented DNA in 1× EcoPol buffer (NEB) or 1× Sequenase buffer (USB), 200 μM of each dNTP, 360 ng of Single Stranded DNA Binding Protein (USB), 200 nM of known Y.sub.U primer (Table III, primer 8), and 500 nM of degenerate Y(N).sub.2 primer (Table III, primer 3) in a final volume of 25 μl. After a denaturing step of 2 min at 95° C., the samples were cooled to 16° C., and the reaction initiated by adding 2.5 units or 6.5 units of Klenow Exo.sup.− polymerase (NEB) or Sequenase version 2 (USB), respectively. WGA library synthesis was carried out in a three-step protocol for 10 min at 16° C., 10 min at 24° C., and 12 min at 37° C. Reactions were stopped with 1 μl of 500 mM EDTA (pH 8.0), and samples were heated for 3 min at 75° C. Aliquots of the library synthesis reactions corresponding to 5 ng of input DNA were further amplified by real-time PCR. The PCR reaction mixture contained: 1× Titanium Taq reaction buffer (Clontech), 200 uM each dNTP, 100,000× dilutions of fluorescein and SybrGreen I (Molecular Probes) 1 uM known Y.sub.U primer (or in the case of random T7(N).sub.6 primers, known T7 (primer 18), 5 units of Titanium Taq polymerase (Clontech), and a volume of the library synthesis reaction corresponding to 5 ng of the input genomic DNA in a final volume of 50 μl. Reactions were carried out for 17 cycles at 94° C. for 15 sec and 65° C. for 2 min on an I-Cycler real-time PCR instrument (Bio-Rad).
(164) The material amplified by PCR with the known Y.sub.U primer was purified with Qiaquick filters (Qiagen), and 10 ng aliquots were analyzed in real-time PCR. Reactions were carried out for 45 cycles at 94° C. for 15 sec and 68° C. for 1 min on I-Cycler (Bio-Rad), as described above in a 25 μl volume. Standards corresponding to 10, 1, and 0.2 ng of fragmented genomic DNA were used for each STS. Quantities were calculated by standard curve fit for each STS (I-Cycler software, Bio-Rad), and plotted as frequency histograms (
Example 4. Comparison of Degenerate Primers Y(N).SUB.2., R(N).SUB.2., M(N).SUB.2 .and K(N).SUB.2 .Comprised of Only Two Non-Complementary Bases and Containing Two Truly Random Bases at their 3′ Terminus in their Efficiency of Human Whole Genome Library Preparation and Amplification
(165) Human lymphocyte genomic DNA isolated by standard procedures was randomly fragmented in TE-L buffer by heating at 95° C. for 4 min. The reaction mixtures (one for each degenerate primer) contained 100 ng of thermally fragmented DNA in 1× EcoPol buffer (NEB), 200 μM of each dNTP, and 1 μM of degenerate Y(N).sub.2, R(N).sub.2, M(N).sub.2, or K(N).sub.2 primers (Table III, primers 3, 10, 12, and 14) in a final volume of 24 After denaturing at 95° C. for 2 min the samples were cooled to 16° C. and the library synthesis reaction was initiated by adding 1 μl (3 units) of Sequenase version 2 (USB Corporation). The reaction was carried out in a three-step protocol for 15 min at 16° C., 15 min at 24° C., and 15 min at 37° C. Reactions were stopped by adding 1 ul of 250 mM EDTA (pH 8.0) and samples were heated for 5 min at 75° C. Aliquots of the library reactions corresponding to 5 ng of input DNA were further amplified by quantitative real-time PCR. The PCR reaction mixture contained: 1× Titanium Taq reaction buffer (Clontech), 200 μM each dNTP, 100,000× dilutions of fluorescein and SybrGreen I (Molecular Probes) 1 uM known Y.sub.U, R.sub.U, M.sub.U, or K.sub.U primer whose sequence is identical to the known 5′ portion of the respective degenerate primer (Table III, primers 8, 11, 13, and 16), 5 units of Titanium Taq polymerase (Clontech), and 5 ng input genomic DNA equivalent of the library synthesis reactions in a final volume of 50 ul. Amplifications were carried out for 16 cycles at 94° C. for 15 sec and 65° C. for 2 min on the I-Cycler real-time PCR instrument (Bio-Rad).
Example 5. Comparison Between Different Modes of Incubation During Preparation of Whole Genome Libraries with Sequenase Version-2 and Y(N)2 Degenerate Primers and Subsequent Representative Amplification of Human DNA
(166) Human lymphocyte genomic DNA isolated by standard procedures was randomly fragmented in TE-L buffer by heating at 95° C. for 4 min. The reaction mixture contained 100 ng of thermally fragmented DNA in 1× EcoPol buffer (NEB), 200 μM of each dNTP, and 1 μM of degenerate Y(N).sub.2 primer (Table III, primer 3) in a final volume of 25 μl. After a denaturing step of 2 min at 95° C., the samples were cooled to 16° C., or 24° C. and the WGA library synthesis reactions were initiated by adding 3 units or of Sequenase version 2 (USB). The reactions were carried out in three different protocols as follows: (i) isothermal 24° C. for 1 hour (ii) cycling between 16° C., 24° C., and 37° C. for 1 min each for total of 19 cycles (total duration 1 hour), and (iii) three step incubation protocol for 20 min at 16° C., 20 min at 24° C., and 20 min at 37° C. Reactions were stopped with 1 μl of 250 mM EDTA (pH 8.0), and samples were heated for 5 min at 75° C. Aliquots of the library synthesis reactions corresponding to 5 ng of input DNA were further amplified by real-time PCR. The PCR reaction mixture contained: 1× Titanium Taq reaction buffer (Clontech), 200 μM each dNTP, 100,000× dilutions of fluorescein and SybrGreen I (Molecular Probes) 1 μM known Y.sub.U primer (or Table III, primer 8), 5 units of Titanium Taq polymerase (Clontech), and 5 ng input genomic DNA of the synthesis reactions in a final volume of 50 μl. Reactions were carried out for 17 cycles at 94° C. for 15 sec and 65° C. for 2 min on I-Cycler real-time PCR instrument (Bio-Rad).
Example 6. Titration of Self-Inert Degenerate Primer K(N).SUB.2 .Concentration in Human Whole Genome Amplification Protocol with Sequenase
(167) Human lymphocyte genomic DNA isolated by standard procedures was randomly fragmented in TE-L buffer by heating at 95° C. for 4 min. The reaction mixture (25 ul) contained 100 ng of thermally fragmented DNA in 1× EcoPol buffer (NEB), 200 μM of each dNTP, and 500 nM, 1 μM, 2 μM, 10 μM, or 33 μM of the self-inert degenerate primer K(N).sub.2 containing G and T bases and 2 completely random bases at the 3′ end (Table III, primer 14). After a denaturing step of 2 min at 95° C., the samples were cooled to 24° C., and the library synthesis reaction was initiated by the addition of 3 units of Sequenase version 2 DNA polymerase (USB). WGA library synthesis was carried out isothermally at 24° C. for 45 min. Reactions were stopped with 1 μl of 250 mM EDTA (pH 8.0), and samples were heated for 5 min at 75° C. Aliquots of the library synthesis reactions corresponding to 5 ng of the input DNA were further amplified by real-time PCR. The PCR reaction mixture contained: 1× Titanium Taq reaction buffer (Clontech), 200 μM each dNTP, 100,000× dilutions of fluorescein and SybrGreen I (Molecular Probes) 1 uM known K.sub.U primer (Table III, primer 16), 5 units of Titanium Taq polymerase (Clontech), and a volume of the library synthesis reaction corresponding to 5 ng of input genomic DNA in a final volume of 50 μl. Reactions were carried out for 15 cycles at 94° C. for 15 sec and 65° C. for 2 min on I-Cycler real-time PCR instrument (Bio-Rad).
Example 7. Titration of the Input Amount of DNA in Human Whole Genome Amplification with Degenerate Primer K(N).SUB.2 .and Sequenase
(168) Human lymphocyte genomic DNA isolated by standard procedures was randomly fragmented in TE-L buffer by heating at 95° C. for 4 min. The reaction mixtures contained 100 ng, 25 ng, 10 ng, or 5 ng of thermally fragmented DNA (or just TE-L buffer as negative control) in 1× EcoPol buffer (NEB), 200 μM of each dNTP, and 1 uM degenerate primer K(N).sub.2 (Table III, primer 14) in a total volume of 15 μl. After a denaturing step of 2 min at 95° C., the samples were cooled to 16° C., and the reaction initiated by adding 1.85 units of Sequenase version 2 DNA polymerase (USB). Library synthesis was done at 16° C. for 20 min 24° C. for 20 min, and 37° C. for 20 min. Reactions were stopped with 1 μl of 83 mM EDTA (pH 8.0), and samples were heated for 5 min at 75° C. Aliquots of the synthesis reactions corresponding to 5 ng of input DNA (or in the case of 5 ng DNA the entire reaction mixture) were further amplified by real-time PCR. The PCR reaction mixture contained: 1× Titanium Taq reaction buffer (Clontech), 200 μM each dNTP, 100,000× dilutions of fluorescein and SybrGreen I (Molecular Probes) 1 μM known K.sub.U primer (Table III, primer 16), 5 units of Titanium Taq polymerase (Clontech), and 5 ng input genomic DNA of the library synthesis reactions in a final volume of 75 μl. Reactions were carried out for 14 cycles at 94° C. for 15 sec and 65° C. for 2 min on I-Cycler real-time PCR instrument (Bio-Rad).
(169) Genomic libraries described herein provide a very efficient resource for highly representative whole genome amplification. Size (200-2,000 bp) and a known priming (known sequence) site make them also very attractive for such applications as DNA archiving, storing, retrieving and re-amplification. Multiple libraries can be immobilized and stored as micro-arrays. Libraries covalently attached by one end to the bottom of tubes, micro-plates or magnetic beads can be used many times by replicating immobilized amplicons, dissociating replicated molecules for immediate use, and returning the original immobilized WGA library for continuing storage.
(170) The structure of WGA amplicons can also be easily modified to introduce a personal identification (ID) DNA tag to every genomic sample to prevent an unauthorized amplification and use of DNA. Only those who know the sequence of the ID tag will be able to amplify and analyze genetic material. The tags can be useful for preventing genomic cross-contaminations when dealing with many clinical DNA samples
(171) WGA libraries created from large bacterial clones (BACs, PACs, cosmids, etc) can be amplified and used to produce genomic micro-arrays.
(172) The examples presented below describe processes that can enhance the outlined applications of the WGA libraries.
Example 8. Incorporation of Individual Identification DNA Tags by Whole Genome Amplification; Recovery of the Individual WGA Libraries from a Mixture of Several WGA Libraries
(173) This example describes two processes of tagging individual WGA library (ies) with the DNA identification sequence (ID) for the purpose of subsequent recovery of this library from the mixture containing other WGA libraries. Such a situation can occur intentionally or unavoidably, such as when manipulating or storing a very large number of WGA DNA samples, or intentionally, such as when there is a need to prevent unauthorized access to genetic information within the stored libraries.
(174) Both processes involve known primers with known sequence U at the 3′ end and individual ID sequence tag at the 5′ end (
(175) The process of tagging, mixing and recovery of 3 different WGA libraries using replicable known primers is shown on
(176) The process of tagging, mixing and recovery of 3 different WGA libraries using non-replicable known primers is shown in
(177) The processes of tagging and recovery described above for genomic libraries can be similarly applied to individual whole transcriptome libraries.
Example 9. Incorporation of Poly-G and Poly-C Functional Tags into WGA/WTA Libraries for Targeted DNA/RNA Amplification
(178) WGA (or WTA) libraries prepared by the method of library synthesis described in the invention may be modified or tagged to incorporate specific sequences. The tagging reaction may incorporate a functional tag. For example, the functional 5′ tag composed of poly cytosine may serve to suppress library amplification with a terminal C10 sequence as a primer. Terminal complementary homo-polymeric G sequence can be added to the 3′ ends of amplified WGA library by terminal deoxynucleotidyl transferase (
(179) As described in U.S. Patent Application 20030143599, hereby incorporated by reference in its entirety, genomic DNA libraries flanked by homo-polymeric tails consisting of G/C base paired double stranded DNA, or poly-G single stranded 3-extensions, are suppressed in their amplification capacity with poly-C primer. This suppression is caused by reduced priming efficiency at poly G region because of formation of alternative G-quartet-like secondary structure within this sequence and it does not depend on the size of DNA amplicons, in contrast to well known “suppression PCR” that results from “pan-like” double-stranded structures formed by self-complementary adaptors and as a result strongly depends on the size of DNA fragments having been more prominent for shortest amplicons (Siebert et al., 1995; U.S. Ser. No. 00/575,9822A). This suppression effect is diminished for a targeted site when balanced with a second site-specific primer, whereby amplification of a plurality of fragments containing the unique priming site and the universal terminal sequence are amplified selectively using a specific primer and a poly-C primer, for instance primer C.sub.10. Those skilled in the art will recognize that genomic complexity may dictate the requirement for sequential or nested amplifications to amplify a single species of DNA to purity from a complex WGA library.
Example 10. WGA Libraries in the Microarray Format
(180) For archiving purposes, for example, individual WGA libraries can be immobilized, such as, for example, on a micro-array. Micro-array format would allow storing tens or even hundreds or thousands of immortalized DNA samples on one small microchip and have fast automated access to them. There are two principal ways that WGA libraries can be immobilized to a micro-array surface: covalently and non-covalently.
Example 11. Repeated Usage of Immobilized WGA Libraries
(181) Covalently immobilized WGA libraries (or libraries immobilized through the biotin-streptavidin interaction) can be used repeatedly to produce replica libraries for whole genome amplification (
Example 12. Purification of the WGA Products Using a Non-Replicable Primer Affinity Tag and DNA Immobilization by Hybridization
(182) For many applications, purity of the amplified DNA is critical. WGA libraries with 5′ overhangs can be hybridized to complementary oligonucleotides covalently attached to the surface of magnetic beads, tubes or micro-plates, washed with TE buffer or water to remove excess of dNTPs, buffer and DNA polymerase and then released by heating in a small volume of TE buffer. For this purpose, the single stranded 5′-affinity tag can be introduced by using a non-replicable primer (
Example 13. Comparison Between Whole Genome Amplification of Libraries Prepared by Klenow Exo− Fragment of DNA Polymerase I with Self-Inert Primers and DOP-PCR Amplification
(183) This example describes a side-by-side comparison between the whole genome amplification described in the present invention and a commercially available kit for DOP-PCR amplification.
(184) Human lymphocyte genomic DNA was isolated by standard protocol using phenol-chloroform extraction.
(185) For whole genome amplification with Klenow fragment of DNA polymerase I, samples containing 5 ng or 20 pg in 10 μl of TE-L buffer were randomly fragmented by heating at 95° C. for 4 min. Samples were supplemented with a reaction buffer containing final concentrations of 1× EcoPol buffer (NEB), 200 μM of each dNTP, 1 μM degenerate K(N).sub.2 primer (Table III, primer 14), and 15 ng/μl SSB protein (USB) in a total volume of 14 μl. After a denaturing step of 2 min at 95° C., the samples were cooled to 24° C. and the library synthesis reactions were initiated by adding 5 units (1 μl) of Klenow Exo− DNA polymerase (NEB).
(186) After incubation for 60 min at 24° C., reactions were stopped by heating at 75° C. for 5 min. The synthesis reactions were amplified by real-time PCR. The PCR reaction mixture contained: 1× Titanium Taq reaction buffer (Clontech), 200 μM of each dNTP, 100,000× dilutions of fluorescein and SybrGreen I (Molecular Probes) 1 μM universal K.sub.U primer (Table III, primer 16), 5 units of Titanium Taq polymerase (Clontech), and the entire 15 μl library synthesis reactions in a final volume of 75 Reactions were carried out at 94° C. for 15 sec and 65° C. for 2 min on I-Cycler real-time PCR instrument (Bio-Rad).
(187) Amplifications by DOP-PCR were done using DOP PCR Master™ Kit purchased from Roche Molecular Biochemicals (Catalog #1644963). Amplification reactions were carried out under Protocol 2 of the manufacturer's manual. Briefly, samples containing 5 ng or 20 pg of DNA (or control samples without DNA) in a 50 μl standard DOP PCR reaction mixture supplemented with 100,000× dilutions of fluorescein and SybrGreen I (Molecular Probes) were amplified after denaturing for 5 min at 95° C. by cycling for 5 cycles at: 94° C. for 30 sec, 30° C. for 30 sec, ramping at 30° C. to 72° C. for 30 sec (1.4° C./sec), and 72° C. for 1.5 min, followed by 45 cycles at: 94° C. for 30 sec, 62° C. for 30 sec, and 72° C. for 1.5 min, and final extension at 72° C. for 7 min on I-Cycler real-time PCR instrument (Bio-Rad).
(188)
(189) Representation analysis was performed using a panel of 16 random human genome STS markers (Table IV, STS markers: 40, 4-44, 46, 47, 49, 52, 54, 55, 58, 60, 62, 63, and 66). The material amplified by PCR with universal K.sub.U primer was purified with Qiaquick filters (Qiagen), and 10 ng aliquots were analyzed in real-time PCR. Reactions were carried out for 45 cycles at 94° C. for 15 sec and 68° C. for 1 min on I-Cycler (Bio-Rad), in a 25 μl volume. Standards corresponding to 10, 1, and 0.2 ng of fragmented genomic DNA were used for each STS. Quantitation was by standard curve fit for each STS.
(190)
(191) Taken together, these results demonstrate the superiority of the methods in the present invention over the DOP-PCR technique (Telenius et al., 1992), both in terms of sensitivity and fidelity of genome sequence representation.
Example 14: Library Generation and Whole Genome Amplification of DNA Isolated from Serum
(192) This example describes the amplification of genomic DNA that has been isolated from serum collected in serum separator tubes (SST). Blood was collected into 8 ml vacutainer SST tubes. The serum tubes were allowed to sit at room temperature for 30′. The tubes were centrifuged for 10′ at 1,000×G with minimal acceleration and braking. The serum was subsequently transferred to a clean tube. Isolated serum samples may be used immediately for DNA extraction or stored at −20° C. prior to use.
(193) DNA from 1 ml of serum was purified using the DRI ChargeSwitch Blood Isolation kit according to the manufacturer's protocols. The resulting DNA was precipitated using the pellet paint DNA precipitation kit (Novagen) according to the manufacturer's instructions and the sample was resuspended in TE-Lo to a final volume of 30 ml for serum. The quantity and concentration of DNA present in the sample was quantified by real-time PCR using Yb8 Alu primer pairs; Yb8F 5′-CGAGGCGGGTGGATCATGAGGT-3′ (SEQ. ID NO:120), and Yb8R 5′-TCTGTCGCCCAGGCCGGACT-3′ (SEQ. ID NO:121). Briefly, 25 ml reactions were amplified for 40 cycles at 94° C. for 15 sec and 74° C. for 1 min. Standards corresponding to 10, 1, 0.1, 0.01, and 0.001 ng of genomic DNA were used and the serum DNA quantities and concentrations were calculated by standard curve fit (I-Cycler software, Bio-Rad).
(194) DNA isolated from serum was randomly fragmented in TE-L buffer by heating at 95° C. for 4 min. The reaction mixture contained 10 ng of thermally fragmented DNA in 1× EcoPol buffer (NEB), 200 μM of each dNTP, and 1 uM of degenerate K(N).sub.2 primer (Table III, primer 14) in a final volume of 15 After a denaturing step of 2 min at 95° C., the samples were cooled to 4° C. and the reaction initiated by adding 5 units Klenow Exo− (NEB). WGA library synthesis was carried out by a three-step incubation protocol for 20 min at 16° C., 20 min at 24° C., and 20 min at 37° C. Reactions were stopped by heating for 15 min at 75° C. and subsequently cooling to 4° C. The entire library reaction was further amplified by real-time PCR. The PCR reaction mixture contained: 1× Titanium Taq reaction buffer (Clontech), 200 uM each dNTP, 10,000× dilutions of fluorescein and SybrGold I (Molecular Probes) 1 uM known K.sub.U primer (Table III, primer 15), 0.5× Titanium Taq polymerase (Clontech), and 10 ng input genomic DNA of the library reactions in a final volume of Reactions were carried out for 17 cycles at 94° C. for 15 sec and 65° C. for 2 min on an I-Cycler real-time PCR instrument (Bio-Rad). The amplification curve is illustrated in
(195) The amplified material was purified by Millipore Multiscreen PCR plates and quantified by optical density. Gel analysis of the amplified products indicated a size distribution (200 bp to 1.6 kb) similar to the original serum DNA (
Example 15. Whole Genome Amplification of Single Human Cells and Individual Hair Follicles from Libraries Prepared Using Self-Inert Degenerate Primer K and Klenow Exo− Fragment of DNA Polymerase I
(196) This example describes the whole genome amplification of total DNA from single human blood cells, single sperm cells, and individual hair follicles.
(197) Three microliters of freshly drawn blood from a healthy female donor were exponentially diluted in PCR tubes containing 27 μl dilution buffer composed of 10 mM Tris-HCl, pH 7.5, 100 mM NaCl, and 0.5 mM EDTA to a level of 1, 0.5, or 0.2 cells per assuming an average blood count of 5×10.sup.3 nucleated cells per ml of blood. Similarly, 3 μl of ejaculate from a healthy donor were diluted to the same level assuming a sperm count of 20,000 per μl of ejaculate. A single hair follicle from a healthy female donor was lysed as described below and then exponentially diluted in lysis buffer.
(198) One microliter of the respective cell dilutions was mixed with 9 μl of freshly prepared lysis buffer containing 10 mM Tris-HCl, pH 7.5, 0.5 mM EDTA, 20 mM NaCl, 0.007% (w/v) sodium dodecyl sulfate (SDS), and 0.12 mg/ml proteinase K (USB). In the case of a hair follicle, the follicle was suspended in 10 μl of lysis buffer. The samples were incubated for 1 hr at 50° C. to lyse the cells. The hair follicle sample was further sequentially diluted with lysis buffer from 10.sup.2 to 10.sup.6-fold and each dilution was subjected to WGA library preparation.
(199) Samples were heated at 99° C. for 4 min to inactivate the proteinase K, disintegrate the nucleoprotein, and thermally fragment the DNA. The library synthesis step was conducted in a reaction mixture containing 1× EcoPol buffer (NEB), 200 mM of each dNTP, 1 μM degenerate primer K (Table III, sequence ID 15), and 15 ng/μl SSB (USB) in a total volume of 14 After a denaturing step of 2 min at 95° C., the samples were cooled to 24° C. and the reaction initiated by adding 5 units (1 μl) of Klenow Exo− DNA polymerase (NEB). After incubation for 60 min at 24° C. reactions were stopped by heating at 75° C. for 5 min. The synthesized libraries were amplified by real-time PCR. The PCR reaction mixture contained: 1× Titanium Taq reaction buffer (Clontech), 200 uM each dNTP, 100,000× dilutions of fluorescein and SybrGreen I (Molecular Probes) 1 uM universal K.sub.U primer (Table III, primer 16), 5 units of Titanium Taq polymerase (Clontech), and the entire 15 μl library synthesis reaction in a final volume of 75 In the case of hair follicle dilutions a blank control without DNA was included. Redundant single cell samples at different dilutions were amplified which served as auto-controls, i.e. one cell or no cells were amplified at the highest dilutions. Reactions were carried out at 94° C. for 15 sec and 65° C. for 2 min on I-Cycler real-time PCR instrument (Bio-Rad).
(200)
(201) Representation analysis of 5 single cell samples amplified by PCR was done using a panel of 16 human STS markers (Table IV, STS markers: 40, 4-44, 46, 47, 49, 52, 54, 55, 58, 60, 62, 63, and 66). The material amplified by PCR with universal K.sub.U primer was purified with Qiaquick filters (Qiagen), and 10 ng aliquots were analyzed in real-time PCR. Reactions were carried out for 45 cycles at 94° C. for 15 sec and 68° C. for 1 min on I-Cycler (Bio-Rad), in a 25 μl volume. Standards corresponding to 10, 1, and 0.2 ng of fragmented genomic DNA were used for each STS. Quantitation was by standard curve fit for each STS. To assess the effect of copy number on the amplification bias, ⅙ of the volume of each individual single cell amplification reaction was combined into a pooled sample. The pooled sample was analyzed for STS marker representation as described above. Markers amplified at a level of less than 0.2 ng of standard template were considered dropouts. Table V shows the number of dropout markers for 3 individual single cell amplifications, as compared to the pooled sample.
(202) TABLE-US-00005 TABLE V STS markers amplification from whole genome amplified single blood cells and a pool of six individually amplified single cells Markers Amplified % of total # of dropouts (n = 16) Single cell 10 37.5% Single cell 8 50.0% Single cell 10 37.5% Pooled sample 4 75.0%
(203) The majority of genomic marker dropouts were random in individual single cell amplification reactions. After pooling of individually amplified single cells, the number of dropouts decreased by approximately half (Table V).
(204)
(205) As shown on
Example 16. Amplification of Single Human Chromosomes with Degenerate K(N).SUB.0 .Primer and Klenow Exo− Fragment of DNA Polymerase-I
(206) This example describes the amplification of total DNA from single copy human chromosomes.
(207) Single copies of derivative chromosomes from a lymphoblastoid cell line carrying a translocation (11;12)(q21;p13.33) sorted in 5 μl of water in a 96 well microtiter plate were obtained from the Wellcome Trust Sanger Institute. Fourteen individual samples of each translocation derivative chromosome were lysed in freshly prepared lysis buffer containing 10 mM Tris-HCl, pH 7.5, 0.5 mM EDTA, 20 mM NaCl, 0.007% (w/v) sodium dodecyl sulfate (SDS), and 0.12 mg/ml proteinase K (USB) in a final volume of 10 μl at 50° C. for 1 hr.
(208) Samples were heated at 99° C. for 4 min to inactivate the proteinase K, disintegrate the nucleoprotein, and thermally fragment the DNA. Library synthesis was conducted in a reaction mixture containing 1× EcoPol buffer (NEB), 200 μM of each dNTP, 1 mM degenerate K(N).sub.0 primer (Table III, sequence ID 15), and 15 ng/μl SSB (USB) in a total volume of 14 μl. After a denaturing step of 2 min at 95° C., the samples were cooled to 24° C. and the reaction initiated by adding 5 units (1 μl) of Klenow Exo− DNA polymerase (NEB). After incubation for 60 min at 24° C. reactions were stopped by heating at 75° C. for 5 min. The library synthesis reactions were amplified by real-time PCR in a mixture contained: 1× Titanium Taq reaction buffer (Clontech), 200 uM each dNTP, 100,000× dilutions of fluorescein and SybrGreen I (Molecular Probes) 1 uM universal K.sub.U primer (Table III, primer 16), 5 units of Titanium Taq polymerase (Clontech), and the entire 15 μl library synthesis reaction in a final volume of 75 μl. Blank controls without DNA were also included. Reactions were carried out at 94° C. for 15 sec and 65° C. for 2 min on I-Cycler real-time PCR instrument (Bio-Rad).
(209)
Example 17. Application of Single-Cell WGA for Detection and Analysis of Abnormal Cells
(210) WGA amplified single-cell DNA can be used to analyze tissue cell heterogeneity on the genomic level. In the case of cancer diagnostics it would facilitate the detection and statistical analysis of heterogeneity of cancer cells present in blood and/or biopsies. In the case of prenatal diagnostics it would allow the development of non-invasive approaches based on the identification and genetic analysis of fetal cells isolated from blood and/or cervical smears. Analysis of DNA within individual cells could also facilitate the discovery of new cell markers, features, or properties that are usually hidden by the complexity and heterogeneity of the cell population.
(211) Analysis of the amplified single-cell DNA can be performed in two ways. In the traditional approach shown on
(212) In the second approach shown on
Example 18. Application of Whole Genome Amplification for Detection and Analysis of Gene Copy Number
(213) WGA amplified DNA retains both sequence and copy number integrity during library synthesis and amplification. This feature of the libraries facilitates the potential evaluation of cells or tissues suspected of having undergone gene amplification events such as those observed in oncogenic transformation. Early detection of gene amplification events requires the ability to examine the event in a few suspect cells or biopsy material. This application is best illustrated with a set of model samples from patients of known chromosomal aneuploidy in the X-chromosome as described in this example.
(214) DNA from patients with XO, XX, and XXX served as template for WGA library synthesis (kindly provided by Dr. Arul Chinnaiyan, University of Michigan). DNA isolated by standard procedures was randomly fragmented in TE-L buffer by heating at 95° C. for 4 min. The reaction mixtures contained 25 ng of thermally fragmented DNA (or just TE-L buffer as negative control) in 1× EcoPol buffer (NEB), 200 μM of each dNTP, and 1 uM degenerate K(N).sub.2 primer (Table III, primer 14) 15 ng/μl SSB (USB) in a total volume of 14 After a denaturing step of 2 min at 95° C., the samples were cooled to 16° C., and the reaction initiated by adding 5 units (1 μl) of Klenow exo− DNA polymerase (USB). WGA library synthesis was done at 16° C. for 20 min 24° C. for 20 min, and 37° C. for 20 min. Reactions were stopped with 1 μl of 83 mM EDTA (pH 8.0), and samples were heated for 5 min at 75° C. Aliquots of the reactions corresponding to 5 ng of input DNA were amplified by real-time PCR. The PCR reaction mixture contained: 1× Titanium Taq reaction buffer (Clontech), 200 μM each dNTP, 100,000× dilutions of fluorescein and SybrGreen I (Molecular Probes) 1 μM known K.sub.U primer (Table III, primer 16), 5 units of Titanium Taq polymerase (Clontech), and 5 ng input genomic DNA of the library synthesis reactions in a final volume of 75 Reactions were carried out for 14 cycles at 94° C. for 15 sec and 65° C. for 2 min on I-Cycler real-time PCR instrument (Bio-Rad).
(215) For analysis, individual 5 ng aliquots of the library were compared to the combined mixture reconstituting the entire 25 ng input template using X chromosome STS primer pairs (152 and 154 Table IV). The material amplified by PCR with universal K.sub.U primer was purified with Qiaquick filters (Qiagen), and 10 ng aliquots were analyzed in real-time PCR. Reactions were carried out for 40 cycles at 94° C. for 15 sec and 68° C. for 1 min on I-Cycler (Bio-Rad), in a 25 μl volume.
(216)
(217) The precise copy number measurements shown here for WGA amplified libraries exemplify the potential for clinical applications in gene amplification events. Combined with the ability to generate libraries from low amounts of template the invention can be used in cancer and prenatal diagnostics where DNA sample is frequently very limited.
Example 19. Whole Transcriptome Amplification Using Libraries Prepared from Poly A+ RNA by MMLV Reverse Transcriptase and Self-Inert Degenerate Primers
(218) This example describes application of the invention for the creation of an amplifiable library faithfully representing the expression patterns of transcribed RNA within a cell or population of cells herein termed “Whole Transcriptome Amplification” (WTA).
(219) Purified polyA+ RNA from EBV transformed human B lymphocytes, Raji cells (Clontech), served as input template for WTA library preparation. As in the case of WGA protocol, WTA is performed in two steps: library synthesis and library amplification. Library synthesis involves similar self-inert degenerate primers (primers K), but a different DNA polymerase, specifically MMLV reverse transcriptase. It proceeds through the extension/strand displacement reactions similar to WGA, but requires no fragmentation of the RNA template (although fragmentation can be applied to reduce the average amplicon size if desireable). To improve representation of the 3′ termini of mRNA molecules primer K(T).sub.20 (Table III primer 19) complementary to the polyA tails was also added. To assemble the library synthesis reaction, primers were annealed to polyA+ RNA templates. Annealing was facilitated by briefly heating the mixture of 100 ng or 10 ng polyA+ RNA, primers K(N).sub.2 [1 μM] (Table III primer 14) and K(T).sub.20 [200 nM] (Table III primer19) either in combination, or K(N).sub.2 [1 μM] alone, dNTP mix [1 μM ea.] and RNase free water to 17 μl at 70° C. for 5 minutes followed by immediate removal to ice. The polymerase reaction was initiated by addition of 2 μl of 10×MMLV buffer to a final concentration of 75 mM KCL, 50 mM Tris-HCl, 3 mM MgCl.sub.2, 10 mM dithiothreitol, pH 8.3) and 1 μl (200 units) MMLV reverse transcriptase (NEB). Reactions were mixed, and incubated for 1 hour at 42° C. Enzyme activity was halted by heat inactivation for 5 minutes at 95° C.
(220) Aliquots of the WTA library synthesis reactions corresponding to 10 ng of input RNA (or in the case of the 10 ng sample, the entire reaction mixture) were further amplified by real-time PCR. The PCR reaction mixture contained: 1× Titanium Taq reaction buffer (Clontech), 200 nM each dNTP, 100,000× dilutions of fluorescein and SyberGreen I (Molecular Probes) 1 μM K.sub.U primer (Table III primer 16), 5 units of Titanium Taq polymerase (Clontech) and volumes representing 10 ng equivalents of the input polyA+ RNA from the library synthesis reactions in a final volume of 754 Reactions were carried out for 17 cycles (94° C. for 20 sec and 65° C. for 2 min) in real-time PCR I-Cycler™ (Bio-Rad). The effects of input template and subsequent reaction volumes transferred into the PCR amplification are seen in
(221) One specific application of whole transcriptome amplification is to enable micro-array expression analysis from small amounts of RNA. Traditional RNA amplification methods employ priming of polyA tails present within the mRNA pool of transcripts. As a result, the micro-array studies to date have been biased toward the 3′ end of mRNAs. To increase compatibility of the present invention with the existing micro-array target bias, the K(T).sub.20 primer was employed. To demonstrate the effect of this added priming, the amplifications were tested in the presence and absence of each primer.
(222) Agarose gel electrophoretic analysis of the resulting amplified library products supports the observed real-time improvements with higher input template and polyA tail specific priming.
(223) Representation of specific mRNA molecules was evaluated by real-time PCR analysis for 11 specific human STS markers residing in known genes represented in the RNA sample at various levels of expression (Table IV, STS markers: 20, 31, 47, 51, 86, 103, 106, 110, 119, 134, 140). The material amplified by PCR with universal K.sub.U primer was purified with Qiaquick filters (Qiagen), and 10 ng aliquots were analyzed in real-time PCR. Reactions were carried out for 45 cycles at 94° C. for 15 sec and 68° C. for 1 min on I-Cycler (Bio-Rad), in a 25 μl volume. Standards corresponding to 10, 1, and 0.2 ng of fragmented genomic DNA were used for each STS. Quantitation was by standard curve fit for each STS.
(224) Another unique feature of the invention relates to WTA library representation across a particular mRNA locus. One can expect that the combined terminal and semi-random internal priming generates amplicons across the entire RNA molecule population without bias toward the 3′ end. To prove this statement three large transcripts were examined using STS primer pairs at varying distances from the 3′ end (Table IV STS 42, 42a, 42b, 85, 85a, 85b, 119, 119a, 119b).
Example 20. Whole Transcriptome Amplification: Titration of Input Template and MgCl.SUB.2 .Concentration
(225) WTA amplification of RNA from systematic sampling of tissues such as biopsy tissues and laser capture micro-dissection, or where sample is limiting as in the case of rare collections from unique cohorts, dictates the need for robust amplification from low input template amounts. To evaluate the tolerated range of input template and optimal MgCl.sub.2 concentration, total RNA from normal pooled prostate (CPP, Clontech) was examined from 0.25 ng to 10 ng at 3 mM and 10 mM MgCl.sub.2. Annealing was facilitated by briefly heating the mixture of 10 ng, 1 ng, 0.5 ng, or 0.25 ng CPP total RNA (Clontech), primers K(N).sub.2 [1 μM] (Table III primer 14) and K(T20) [200 nM] (Table III; primer19), dNTP mix [1 μM ea.] and RNase free water to 17 μl at 70° C. for 5 minutes followed by immediate removal to ice. The library synthesis reaction was initiated by addition of 2 μl of 10×MMLV buffer to a final concentration of 75 mM KCL, 50 mM Tris-HCl, 3 mM or 10 mM MgCl.sub.2, 10 mM dithiothreitol, pH 8.3) and 1 μl (200 units) MMLV reverse transcriptase (NEB) or 1 μl (50 units) MMLV reverse transcriptase (Epicentre). Reactions were mixed, and incubated for 1 hour at 42° C. Enzyme activity was halted by heat inactivation for 5 minutes at 95° C.
(226) The library synthesis reactions were amplified by real-time PCR in a reaction mixture that contained: 1× Titanium Taq reaction buffer (Clontech), 200 nM each dNTP, 100,000× dilutions of fluorescein and SyberGreen I (Molecular Probes) 1 μM K.sub.U primer (Table III primer 16), 5 units of Titanium Taq polymerase (Clontech) and 50% of the library synthesis reaction (12.5 μl) representing 5 ng, 0.5 ng, 0.25 ng and 0.125 ng of starting template in a final volume of 75 μl. Reactions were carried out for 17-33 cycles (94° C. for 20 sec and 65° C. for 2 min) in real-time PCR I-Cycler™ (Bio-Rad).
(227) To evaluate the variation in representation across the input template concentration and buffer conditions, samples from 10 ng and 0.25 ng input template amounts were evaluated by STS analysis. Representation of specific mRNA molecules was evaluated by real-time PCR analysis for 11 specific human STS markers residing in known genes represented in the RNA sample at various levels of expression (Table IV, STS markers: 20, 31, 47, 51, 86, 103, 106, 110, 119, 134, 140). The material amplified by PCR with universal K.sub.U primer was purified with Qiaquick filters (Qiagen), and 10 ng aliquots were analyzed in real-time PCR. Reactions were carried out for 45 cycles at 94° C. for 15 sec and 68° C. for 1 min on I-Cycler (Bio-Rad), in a 25 μl volume. Standards corresponding to 10, 1, and 0.2 ng of fragmented genomic DNA were used for each STS. Quantitation was by standard curve fit for each STS.
(228) To further examine the difference between the buffer systems, a titration of MgCl.sub.2 concentration was examined. Total RNA from normal pooled prostate (CPP, Clontech) 10 ng was amplified over a 3-12 mM range of MgCl.sub.2. Annealing was facilitated by briefly heating the mixture of 10 ng CPP total RNA (Clontech), primers K(N).sub.2 [1 μM] (Table III, primer 14) and K(T).sub.20 [200 nM] (Table III, primer19), dNTP mix [1 μM ea.] and RNase free water to 17 μl at 70° C. for 5 minutes followed by immediate removal to ice. The library synthesis reaction was initiated by addition of 2 μl of 10×MMLV buffer to a final concentration of 75 mM KCL, 50 mM Tris-HCl, 3 mM or supplemented in 1 mM increments to 12 mM MgCl.sub.2, 10 mM dithiothreitol, pH 8.3) and 411 (50 units) MMLV reverse transcriptase (Epicentre). Reactions were mixed, and incubated for 1 hour at 42° C. Enzyme activity was halted by heat inactivation for 5 minutes at 95° C. The library synthesis reactions were further amplified by real-time PCR in a reaction mixture that contained: 1× Titanium Taq reaction buffer (Clontech), 200 nM each dNTP, 100,000× dilutions of fluorescein and SyberGreen I (Molecular Probes) 1 μM K.sub.U primer (Table III, primer 16), 5 units of Titanium Taq polymerase (Clontech) and 50% of each library synthesis reaction (10 μl) representing 5 ng of starting template in a final volume of 75 μl. Reactions were carried out for 19 cycles (94° C. for 20 sec and 65° C. for 2 min) in real-time PCR I-Cycler™ (Bio-Rad).
Example 21. Preferential Amplification of Single Stranded Nucleic Acid Templates Using WTA Methods
(229) In applications where residual DNA may be present in a clinical sample, or where total nucleic acids are isolated, the ability to selectively amplify DNA or RNA from the same sample can be beneficial. In this example, the WTA protocol is applied to samples of total RNA or genomic DNA with and without fragmentation and denaturation.
(230) To evaluate WTA library formation from DNA and RNA input templates 10 ng samples of genomic DNA (Coriell CEPH genomic DNA (#7057) or total RNA (Clontech, CPP) were diluted to a final volume of 6.5 μl in water. Fragmentation and denaturation were performed by heating to 95° C. for 4 minutes, snap cooling to ice (4° C.), addition of 1.5 μl of 10×MMLV buffer (Epicentre) to a final concentration of 75 mM KCL, 50 mM Tris-HCl, 10 mM MgCl.sub.2, 10 mM dithiothreitol, pH 8.3), primers K(N).sub.2 [1 μM] (Table III primer 14) and K(T).sub.20 [200 nM] (Table III, primer19), dNTP mix [1 μM ea.] and RNase free water to 14 followed by a brief 2 minute heating to 95° C. and cooling to ice to anneal primers. Samples not fragmented or denatured received standard 70° C. treatment for 5 minutes, followed by snap cooling to ice (4° C.) addition of 1.5 μl of 10×MMLV buffer (Epicentre) to a final concentration of 75 mM KCL, 50 mM Tris-HCl, 10 mM MgCl.sub.2, 10 mM dithiothreitol, pH 8.3), primers K(N).sub.2 [1 μM] (Table III primer 14) and K(T).sub.20 [200 nM] (Table III, primer19), dNTP mix [1 μM ea.] and RNase free water to 14 The polymerase reaction was initiated by addition of 1 μl (50 units) MMLV reverse transcriptase (Epicentre). Reactions were mixed, and incubated for 15 minutes at 23° C. followed by 1 hour at 42° C. Enzyme activity was halted by heat inactivation for 5 minutes at 95° C.
(231) The library reactions were amplified by real-time PCR in a reaction mixture that contained: 1× Titanium Taq reaction buffer (Clontech), 200 nM each dNTP, 100,000× dilutions of fluorescein and SyberGreen I (Molecular Probes) 1 μM K.sub.U primer (Table III primer 16), 5 units of Titanium Taq polymerase (Clontech) and 100% of the library reaction (15 μl) representing the entire 10 ng of starting template in a final volume of 75 μl. Reactions were carried out for 13-17 cycles (94° C. for 20 sec and 65° C. for 2 min) in real-time PCR I-Cycler™ (Bio-Rad).
(232) The ability to distinguish between DNA and RNA templates on the basis of fragmentation and denaturation demonstrate controlled differential access of the template. Residual traces of DNA in RNA preparations will amplify with approximately 1% efficiency with respect to the RNA template under non-denaturing conditions. Although not specifically demonstrated here, as known in the art, Klenow exo− fails to utilize RNA as a template, thereby providing a method to selectively amplify each nucleic acid population from a complex mixture.
Example 22. Total Nucleic Acid Differential Amplification Platform for Synthesis of DNA and RNA Libraries from Limited Archived or Clinical Samples
(233) In some genetic profiling studies, both the genomic (DNA) and the expression (RNA) information are required to provide a complete analysis of the tissue or cells evaluated. Only when alterations in gene sequence, copy number, and the effective expression of transcribed sequences are taken together can a complete analysis of the sample be achieved. In many cases, a clinical isolate or archival sample is limited and may only be sufficient for one isolation scheme. Amplification of genomic and expression libraries may be streamlined through a total amplification platform using the present invention.
(234)
Example 23. Application of Homopolymeric G/C Tagged WGA Libraries for Targeted DNA Amplification
(235) Targeted amplification may be applied to genomes for which limited sequence information is available or where rearrangement or sequence flanking a known region is in question. For example, transgenic constructs are routinely generated by random integration events. To determine the integration site, directed sequencing or primer walking from sequences known to exist in the insert may be applied. The invention described herein can be used in a directed amplification mode using a primer specific to a known region and a universal primer. The universal primer is potentiated in its ability to amplify the entire library, thereby substantially favoring amplification of product between the specific primer and the universal sequence, and substantially inhibiting the amplification of the whole genome library.
(236) Conversion of WGA libraries for targeted applications involves incorporation of homo-polymeric terminal tags. Amplification of libraries with C-tailed universal primers exhibit a dependence on the length of the 5′ poly-C extension component of the primer. WGA libraries prepared by the methods described in the invention can be converted for targeted amplification by PCR re-amplification using poly-C extension primers.
(237) To demonstrate the suppression of library amplification imposed by poly-C tagging, libraries were purified using Qiaquick PCR purification column (Qiagen) and subjected to PCR amplification with poly-C primers corresponding to the length of their respective tag.
Example 24. Application of Homopolymeric G/C Tagged WGA Libraries for Multiplexed Targeted DNA Amplification
(238) Application of G/C tagged libraries for targeted amplification uses a single specific primer to amplify a plurality of library amplimers. The complexity of the target library dictates the relative level of enrichment for each specific primer. In low complexity bacterial genomes a single round of selection is sufficient to amplify an essentially pure product for sequencing or cloning purposes, however in high complexity genomes a secondary, internally “nested”, targeting event may be necessary to achieve the highest level of purity.
(239) Using a human WGA library with C.sub.10 tagged termini incorporated by re-amplification with C-tailed universal U primers, specific sites were targeted and the relative enrichment evaluated in real-time PCR.
(240) To apply targeted amplification in a multiplexed format, specific primer concentrations were reduced 5 fold (from 200 nM to 40 nM) without significant loss of enrichment of individual sites (
(241) To evaluate the utility of multiplex-targeted amplification, a set of primers were designed adjacent to STS sites (Table IV) using Oligo Version 6.53 primer analysis software (Molecular Biology Insights, Inc.: Cascade Colo.). Primers were 18-25 bases long, having high internal stability, low 3′-end stability, and melting temperatures of 57-62° C. (at 50 mM salt and 2 mM MgCl.sub.2). Primers were designed to meet all standard criteria, such as low primer-dimer and hairpin formation, and are filtered against a human genomic database 6-mer frequency table. Primary multiplexed targeted amplification of G/C tagged WGA libraries was performed using 10-50 ng of tagged WGA library, 10-40 nM each of 45 specific primers (Table VI), 200 nM C.sub.10 primer, dNTP mix, 1×PCR buffer and 1× Titanium Taq polymerase (Clontech), FCD (1:100,000) and SGI (1:100,000) dyes (Molecular Probes) added for real-time PCR detection using the I-Cycler (Bio-Rad). Amplification is carried out by heating the samples to 95° C. for 3′30″, followed by 18-24 cycles of 94° C. 20″, 68° C. 2′. The cycle number to reaction plateau is dependent on the absolute template and primer concentrations. The amplified material was purified by Qiaquick spin column (Qiagen), and quantified spectrophotometrically.
(242) The enrichment of each site was evaluated using real-time PCR. Quantitative Real-Time PCR was performed using an I-Cycler Real-Time Detection System (Bio-Rad), as per the manufacturer's directions. Briefly, 25 μl reactions were amplified for 40 cycles at 94° C. for 15 sec and 68° C. for 1 min. Standards corresponding to 10, 1, and 0.2 ng of fragmented DNA were used for each STS, quantities were calculated by standard curve fit for each STS (I-Cycler software, Bio-Rad) and were plotted as distributions.
(243) Secondary targeted amplifications were performed using primary targeting products as template and secondary nested primers (Table VI) in combination with the universal C.sub.10 primer. Reactant concentrations and amplification parameters were identical to primary amplifications above. Multiplexed secondary amplifications were purified by Qiaquick spin column (Qiagen) and quantified by spectrophotometer. Enrichment of specific sites was evaluated in real-time PCR using an I-Cycler Real-Time Detection System (Bio-Rad), as per the manufacturer's directions. Briefly, 25 μl reactions were amplified for 40 cycles at 94° C. for 15 sec and 68° C. for 1 min. Standards corresponding to 10, 1, and 0.2 ng of fragmented DNA were used for each STS, quantities were calculated by standard curve fit for each STS (I-Cycler software, Bio-Rad) and were plotted as distributions.
(244) Targeted amplification applied in this format reduces the primer complexity required for multiplexed PCR. The resulting pool of amplimers can be evaluated on sequencing or genotyping platforms.
Example 25. Non-Redundant Genomic Sequencing of Unculturable or Limited Species Facilitated by Whole Genome and Targeted Amplification
(245) Whole genome and targeted amplification provide a unique opportunity for sequencing genomes of microorganisms which are difficult to grow or for species that are already extinct. The diagram illustrating such a hypothetical DNA sequencing project is shown on the FIG. 50. First, limited amounts of DNA for the organism of interest (
(246) TABLE-US-00006 TABLE VI Targeted Amplification Primers Primary Secondary STS 1P GCATATCCATATCTCCCGAAT STS 1S TAAGCAGCAAGGTCTGGG (SEQ ID NO: 30) (SEQ ID NO: 75) STS 2P CAGAGCACTCCAGACCATACG STS 2S GTGATTGAACAATTTGGACCCAC (SEQ ID NO: 31) (SEQ ID NO: 76) STS 3P CTTCGTTATGACCCCTGCTCC STS 3S ATGGCAACATTCCACCTAGTAGC (SEQ ID NO: 32) (SEQ ID NO: 77) STS 4P TCCCAAGATGAATGGTAAGACG STS 4S CTCCGTCATGATAAGATGCAGT (SEQ ID NO: 33) (SEQ ID NO: 78) STS 5P TCCAATCTCATCGGTTTACTG STS 5S ACTGTTTGGGGTGTGAAAGGAC (SEQ ID NO: 34) (SEQ ID NO: 79) STS 8P TCCAGAGCCCAGTAAACAACA STS 8S ACTAACAACGCCCTTTGCTC (SEQ ID NO: 35) (SEQ ID NO: 80) STS 10P TTACTTCAGCCCACATGCTTC STS 10S TCAGCACTCCGTATCTTCATTTG (SEQ ID NO: 36) (SEQ ID NO: 81) STS 12P TTCCGACATAGCGACTTTGTAG STS 12S TAAACCGCTAAAACGATAGCAGC (SEQ ID NO: 37) (SEQ ID NO: 82) STS 14P AAGGATCAGAGATACCCCACGG STS 14S TCATGGTATTAGGGAAGTGGGAG (SEQ ID NO: 38) (SEQ ID NO: 83) STS 16P TCCAAGAACCAACTAAGTCCAGA STS 16S GGGAATGAAAAGAAAAGGCATTC (SEQ ID NO: 39) (SEQ ID NO: 84) STS 22P CTAAGGGCAAACATAGGGATCAA STS 22S TCTTTCCCTCTACAACCCTCTAACC (SEQ ID NO: 40) (SEQ ID NO: 85) STS 26P CAACCTTTGAAGCCACTTTGAC STS 26S CAGTACATGGGTCTTATGAGTAC (SEQ ID NO: 41) (SEQ ID NO: 86) STS 29P GCCTCCGTCATTGGTATTTTCT STS 29S AATCGAGAACGCACAGAGCAGA (SEQ ID NO: 42) (SEQ ID NO: 87) STS 30P TGGCAACACGGTGCTGACCTG STS 30S GTCTGGGGAGTAAATGCAACATC (SEQ ID NO: 43) (SEQ ID NO: 88) STS 31P ATCATGGGTTTGGCAGTAAAGC STS 31S TTCTTGATGACCCTGCACAA (SEQ ID NO: 44) (SEQ ID NO: 89) STS 35P AGAACCAGCAAACCCAGTCCC STS 35S CAGCAGAAGCACTACCAAAGACA (SEQ ID NO: 45) (SEQ ID NO: 90) STS 36P GAAAGGGTGGATGGATTGAAA STS 36S TTCACCTAGATGGAATAGCCACC (SEQ ID NO: 46) (SEQ ID NO: 91) STS 38P TCAGATTTCCTGGCTCCGCTT STS 38S GCAAGATTTTTGCTTGGCTCTAT (SEQ ID NO: 47) (SEQ ID NO: 92) STS 41P CCTTCTGCTTCCCTGTGACCT STS 41S GAATTTTGGTTTCTTGCTTTGG (SEQ ID NO: 48) (SEQ ID NO: 93) STS 42P TGAACCCCACGAGGTGACAGT STS 42S GTCAGAAGACTGAAAACGAAGCC (SEQ ID NO: 49) (SEQ ID NO: 94) STS 43P GACATTACCAGCCCCTCACCTA STS 43S CATCTCTTGATCATCCCAGCTCT (SEQ ID NO: 50) (SEQ ID NO: 95) STS 44P TCCTTGACAGTTCCATTCACCA STS 44S CACCATTGGTTGATAGCAAGGTT (SEQ ID NO: 51) (SEQ ID NO: 96) STS 46P TTTGCAGGTAGCTCTAGGTCA STS 46S TAAACATAGCACCAAGGGGC (SEQ ID NO: 52) (SEQ ID NO: 97) STS 47P GCGGACAGAGAGTAACCTCGGA STS 47S TCATGTGTGGGTCACTAAGGATG (SEQ ID NO: 53) (SEQ ID NO: 98) STS 49P CCCAGAAACCCTGAGACCCTC STS 49S CGTCTCTCCCAGCTAGGATG (SEQ ID NO: 54) (SEQ ID NO: 99) STS 52P TGTGCCACAAGTTAAGATGCT STS 52S CTTTTTCACAGAACTGGTGTCAGG (SEQ ID NO: 55) (SEQ ID NO: 100) STS 54P TGCTGTATCGTGCCTGCTCAAT STS 54S ACCCAGCTTTCAGTGAAGGA (SEQ ID NO: 56) (SEQ ID NO: 101) STS 60P TGCCCCACTCCCCAACATTCT STS 60S AATCAAAAGGCCAACAGTGG (SEQ ID NO: 57) (SEQ ID NO: 102) STS 62P AACAGAGCCTCAGGGACCAGT STS 62S ACTGGCTGAGGGAGCATG (SEQ ID NO: 58) (SEQ ID NO: 103) STS 70P GGGCTTTGTCTGTGGTTGGTA STS 70S TAAATGTAACCCCCTTGAGCC (SEQ ID NO: 59) (SEQ ID NO: 104) STS 72P TGGGCTGGCTGAGGTCAAGAT STS 72S TATTGACCACATGACCCCCT (SEQ ID NO: 60) (SEQ ID NO: 105) STS 74P TTTTGCTCCGCTGACATTTGG STS 74S TTGGGTGATGTCTTCACATGG (SEQ ID NO: 61) (SEQ ID NO: 106) STS 77P TGCTCCTGTCCCTTCCACTTC STS 77S GCTCAATAAAAATAGTACGCCC (SEQ ID NO: 62) (SEQ ID NO: 107) STS 79P CCTTATTCCCAGCAGCAGTATTC STS 79S TTCTCCCAGCTTTGAGACGT (SEQ ID NO: 63) (SEQ ID NO: 108) STS 82P TGGGAAGGGAAAGAGGGTACT STS 82S TTTGTTACTTGCTACCCTGAG (SEQ ID NO: 64) (SEQ ID NO: 109) STS 83P TTGCTGTAGATGGGCTTTCGT STS 83S GAAGATGAAGTGAACTCCTATCC (SEQ ID NO: 65) (SEQ ID NO: 110) STS 84P TCTGCTGGGTTGATGATTTGG STS 84S GAAGCCTTGATAACGAGAGTGG (SEQ ID NO: 66) (SEQ ID NO: 111) STS 85P GGCACAAGCAAAAGGGTGTCT STS 85S ATGTTTCTCTGGCCCCAAG (SEQ ID NO: 67) (SEQ ID NO: 112) STS 86P CCAGCAATCAGGAAAGCACAA STS 86S TGGCTGCCCTTCAATAC (SEQ ID NO: 68) (SEQ ID NO: 113) STS 89P CACCTGTCTTGTTGGCATCACC STS 89S TTGGGAAATGTCAGTGACCA (SEQ ID NO: 69) (SEQ ID NO: 114) STS 92P TTGTTTTGCCTCACCAGTCATTT STS 92S TGTGGTTAGGATAGCACAAGCATT (SEQ ID NO: 70) (SEQ ID NO: 115) STS 96P TCAGCAAACCCAAAGATGTTA STS 96S TGCAATTTGAAGGTACGAGTAG (SEQ ID NO: 71) (SEQ ID NO: 116) STS 99P TTAGTCCTTTGGGCAGCACGA STS 99S TGTTAACAATTTGCATAACAAAAGC (SEQ ID NO: 72) (SEQ ID NO: 117) STS103P TGTCTCTGCTTCTGAAACGGG STS1035 GCATTTTCTGTCCCACAAGATATG (SEQ ID NO: 73) (SEQ ID NO: 118) STS113P ACTGCCAGGGTCATTGACTT STS1135 ATTGCTGTCACAGCACCTTG (SEQ ID NO: 74) (SEQ ID NO: 119) *P- denotes primary targeted amplification primer *S- denotes secondary targeted amplification primer
Example 26. Universality of the Novel Nucleic Amplification Method and its Compatibility with Different Sources of DNA and RNA and Different Methods of Analysis of the Amplified Material
(247) The diagram presented on
(248) Nucleic acid sources include but not limited to all animals (including humans), plants, fungi, culturable and non-culturable bacteria and viruses, and extinct species found in amber and stones. They can be isolated from any fresh, frozen, or paraffin embedded formalin fixed tissue, body fluids, forensic sample, cell culture, single cell, single chromosome, etc.
(249) The library preparation step can use total nucleic acid as a template (the protocol shown in central part of the diagram, arrow A), and result in the amplification of both DNA and RNA, or use purified DNA, and result in the amplification of the whole genome (the protocol shown in left part of the diagram, arrow B), or use purified RNA, and result in the amplification of the whole transcriptome (the protocol shown in right part of the diagram, arrow C), or use total nucleic acid and a corresponding selection method, and result in the amplification of the whole genome (the protocol shown in left part of the diagram, arrow D), or whole transcriptome (the protocol shown in right part of the diagram, arrow E).
(250) Library prepared and amplified from total nucleic acid, DNA, or RNA can be modified to incorporate polyC regions at the 5′ end of the universal constant sequence (arrows F and G). C-tailed libraries can be used for targeted amplification and analysis of specific genomic regions or RNA transcripts.
(251) Library prepared and amplified from total nucleic acid, DNA, or RNA can be modified to incorporate other tags (see
(252) Applications of the proposed nucleic acid amplification technology include but not limited to genotyping of small DNA/RNA samples, gene expression analysis, sequencing of un-culturable or extinct organisms, molecular diagnostics of different diseases, prenatal diagnostics, viral/bacterial diagnostics, forensics, etc.
Example 27. Amplification of Genomic DNA from Single Cells Using a Mesophilic DNA Polymerase Followed by Universal-Primer PCR with a Thermostable DNA Polymerase, and Analysis of Locus Representation by Real-Time PCR
(253) This example describes the synthesis of libraries from single cells with Klenow Exo-followed by amplification with Taq DNA polymerase and analysis of their locus representation by real-time PCR.
(254) Immortalized human prostate epithelial RWPE cells were trypsinized, washed three times with PBS, and single cells were collected by Flow Cytometry in 5 ul of TE buffer (10 mM Tris-HCl pH 8.0, 1 mM EDTA). Control samples containing either 5 cells or just TE buffer were also included in the analysis to assess the locus representation of more than one genome equivalent and the amplification background respectively. Cells were immediately frozen on dry ice after collection and stored at 80° C. prior to use.
(255) Wells containing sorted cells were thawed on ice and DNA was extracted by addition of 5 ul of freshly prepared 2× cell lysis buffer comprising: 0.015% SDS, 40 mM NaCl, 20 mM Tris-HCl pH 7.5, 0.2 mM EDTA, 0.24 mg/mL Proteinase K and incubated for 1 hour at 50° C., followed by 4 min at 99° C. Samples were briefly centrifuged and placed on ice. Four μL of library synthesis buffer comprising 37.5 mM Tris-HCl pH 7.5, 18.75 mM MgCl.sub.2, 28.125 mM DTT, 0.75 mM each dNTP, 0.05 mg/mL E. coli SSB, and oligonucleotide 3 (Table VII, SEQ ID NO:128) were added to each well and the samples were heated at 95° C. for 2 min and cooled on ice.
(256) Library synthesis was initiated by addition of 1 μl of Klenow exo at 5 Units/uL. Samples were incubated in a thermal cycler as follows: 16° C. for 20 minutes, 24° C. for 20 minutes, 37° C. for 20 minutes, 75° C. for 5 minutes. Libraries were further amplified to saturation by real-time PCR on BioRad i-Cycler by addition of 60 ul of library amplification buffer comprising: 1.25× Titanium Taq buffer (BD-Clontech), 0.5 mM each dNTP, 7 mM MgCl.sub.2, 2.5 uM oligonucleotide 4 (Table VII, SEQ ID NO:129), 0.6× Titanium Taq DNA polymerase (BD-Clontech), and 10000:1 dilutions of fluorescein calibration dye and SybrGreen I (Life Technologies). After initial denaturation at 95° C. for 3 min samples were incubated for 29 cycles at 94° C. for 30 sec and 68° C. for 2 min. Library DNA was purified using MultiScreen HTS PCR kit (Millipore Cat #MSNU03050) following manufacturer's instructions, quantified using absorbance at 260 nm, and 50 ng aliquots were used in locus-specific PCR for representation analysis.
(257) Results show exemplary amplification of 4 individual libraries from sorted single cells, one library of sorted 5 cells, and duplicate “no cells” controls. Locus representation of libraries from sorted cells was analyzed by real-time PCR using a panel of 40 human genomic STS and promoter assays (Table VIII). The PCR reaction mixture comprised: 1× Titanium Taq reaction buffer (Clontech), 200 uM each dNTP, 0.2 uM of each forward and reverse primer, 0.5 ul of Titanium Taq polymerase (Clontech), 50 ng library DNA, and 5000:1 dilutions of fluorescein and SybrGreen I (Life Technologies) in a final volume of 25 ul. In the case of analyzing promoter sequences 4% DMSO and 0.5 M betaine were added to the reaction mixture.
(258) After initial denaturation for 3 min reactions were carried out at 95° C. for 20 sec, 68° C. for 1 min, 75° C. for 30 sec, and 80° C. for 15 sec on i-Cycler real-time PCR instrument (BioRad). Statistical analysis of data was performed using Excel (Microsoft).
Example 28. Amplification of Genomic DNA from Single Cells Using a Thermostable DNA Polymerase and Analysis of Locus Representation by Real-Time PCR
(259) This example describes the amplification of genomic DNA from single cells sorted by Flow Cytometry and the analysis of its locus representation by real-time PCR.
(260) Immortalized human prostate epithelial RWPE cells were trypsinized, washed three times with PBS and single cells were collected by Flow Cytometry into 5 ul of cell lysis buffer comprising 5 mM Tris-HCl pH 8.3, and 0.01% Triton X-100 in deionized nuclease-free water. Control samples containing either 5 cells or just lysis buffer (no cells) were also included in the analysis to assess the locus representation of more than one genome equivalent and the amplification background respectively. Cells were immediately frozen on dry ice after collection and stored at −80° C. prior to use.
(261) Wells containing sorted cells were thawed on ice and DNA was extracted by addition of 4 ul of cell lysis buffer containing 0.2 units of proteinase enzyme (prepGEM Saliva 500 Kit, VWR Catalog #95044-052) and incubated for 10 min at 75° C. Five ul of library preparation buffer comprising: 3×KAPA 2G Robust buffer B (KAPA Biosystems, Cat #KB 5003), 0.6 mM each dNTP, 6 mM MgCl.sub.2, 12% DMSO, 6 uM oligonucleotide 1 (Table VII, SEQ ID NO:25) [or alternatively 15 uM oligonucleotide 5 (Table VII, SEQ ID NO:130)] were added to each well and the samples were heated at 95° C. for 4 min.
(262) Library synthesis was initiated by addition of 1 ul of KAPA 2G Robust DNA polymerase (KAPA Biosystems, Cat #KE 5004) at a concentration of 1 unit/ul. After initial denaturation for 2 min at 95° C. samples were incubated for 12 cycles at: 95° C. for 15 sec, 15° C. for 50 sec, 25° C. for 40 sec, 35° C. for 30 sec, 65° C. for 40 sec, and 75° C. for 40 sec.
(263) Libraries were further amplified to saturation by real-time PCR on BioRad Cycler by addition of 60 ul of library amplification buffer comprising: 1.25×KAPA 2G Robust buffer B (KAPA Biosystems, Cat #KB 5003), 0.5 mM each dNTP, 3.75 mM MgCl.sub.2, 6.25% DMSO, 2.5 uM oligonucleotide 2 (Table VII, SEQ ID NO:26), 4.5 units of KAPA 2G Robust DNA polymerase (KAPA Biosystems, Cat #KE 5004), and 5000:1 dilutions of fluorescein calibration dye and SybrGreen I (Life Technologies).
(264) After initial denaturation at 95° C. for 2 min samples were incubated for 13 cycles at 96° C. for 15 sec, 65° C. for 1 min, and 75° C. for 1 min. Library DNA was purified using MultiScreen HTS PCR kit (Millipore Cat #MSNU03050), and 50 ng aliquots were used in locus-specific PCR for representation analysis.
(265) Locus representation of libraries from sorted cells was analyzed by real-time PCR using a panel of 40 human genomic STS and promoter assays (Table VIII). The PCR reaction mixture comprised: 1× Titanium Taq reaction buffer (Clontech), 200 uM each dNTP, 0.2 uM of each forward and reverse primer, 0.5 ul of Titanium Taq polymerase (Clontech), 50 ng library DNA, and 5000:1 dilutions of fluorescein and SybrGreen I (Life Technologies) in a total volume of 25 ul. In the case of analyzing promoter sequences 4% DMSO and 0.5 M betaine were also added to the reaction mixture. After initial denaturation for 3 min reactions were carried out at 95° C. for 20 sec, 68° C. for 1 min, 75° C. for 30 sec, and 80° C. for 15 sec on i-Cycler real-time PCR instrument (BioRad). Statistical analysis of data was performed using Excel (Microsoft).
(266)
(267) An exemplary amplification of 10 individual libraries from sorted single cells, duplicate sorted 5 cells, and quadruplicate “no cells” controls is shown on
(268)
(269) In quantitative genome analysis sample to sample variation represents a significant problem.
(270)
Example 29. Analyzing Amplification Efficiency
(271) Sample amplification efficiencies can be analyzed by performing the amplification reactions with SYBR® Green I in a real-time thermal cycler. During the amplification reaction, double-stranded amplified molecules are bound by the nonsequence-dependent SYBR® Green I dye, and the accumulation of amplified product is detected as an increase in fluorescence by the real-time instrument.
(272) Data analysis is performed on raw background-subtracted fluorescence, and the instrument/software should be set to the appropriate mode.
(273) Amplification curves will have a similar appearance for successfully amplified single-cell WGA products, with an immediate 8-9 cycle upward sloping phase, followed by a relatively flat “plateau” phase (
(274) No-cell control amplification curves are delayed (right-shift) by 5-6 PCR cycles compared to single-cell amplification curves. A smaller delay of control curves may indicate DNA contamination introduced with the sample or during the WGA process.
Example 30. Protocol
(275) 1. Add 5 uL of PicoPlex Pre-Amp Buffer to 9 uL of single-cell lysate or control no-cell lysate.
(276) 2. Incubate samples in a thermal cycler as follows:
(277) TABLE-US-00007 1 cycle 95 C. 4 min 1 cycle Room Hold Temp
(278) 3. Briefly centrifuge samples. 4. Combine the following components and mix well.
(279) TABLE-US-00008 Synthesis Enzyme Mix Volume Per 5 samples Pre-Amp Enzyme Dilution Buffer 4 uL PicoPlex Pre-Amp Enzyme 1 uL Total Volume 5 uL
(280) 5. Add 1 uL of Pre-Amp Enzyme Mix to sample. 6. Incubate samples according to thermal cycler program below:
(281) TABLE-US-00009 1 cycle 95 C. .sup. 2 min 95 C. 15 sec 15 C. 50 sec 12 cycles 25 C. 40 sec 35 C. 30 sec 65 C. 40 sec 75 C. 40 sec 1 cycle 4 C. hold
(282) 7. Briefly centrifuge samples and place synthesis reaction products on ice. 8. Combine the following Amplification Cocktail components and mix well.
(283) TABLE-US-00010 Amplification Cocktail Volume Per 5 Samples PicoPlex Amplification Buffer 125 uL PicoPlex Amplification Enzyme 4 uL Nuclease-Free Water 171 uL Total Volume 300 uL Note: Sample amplification efficiencies can be analyzed by adding SYBR Green I dye (Invitrogen, S7563) at 0.125x final concentration in the Amplification Cocktail and by performing the amplification in a real-time thermal cycler (see Appendix A). Some instruments may also require additional reference dyes for SYBR signal normalization.
(284) 9. Mix 60 uL of the freshly prepared Amplification Cocktail with the 15 uL synthesis reaction product and mix by pipet. 10. Amplify samples according to thermal cycler program below:
(285) TABLE-US-00011 1 cycle 95 C. 2 min 95 C. 15 sec.sup. 13 cycles 65 C. 1 min 75 C. 1 min Note: 13 cycles is recommended in certain embodiments based on testing performed with single cultured cells obtained by flow sorting, dilution, and micromanipulation. Some cell types or lysis conditions may require additional cycles (up to 15) to obtain maximal yields.
Example 31. Exemplary Kit Materials and Methods
(286) The methods and compositions disclosed herein amplify DNA directly from many types of cells. Some of the methods used in the isolation and amplification of DNA from cells are as follows:
(287) Single Cell Collection Methods
(288) Flow sorting, dilution, and micromanipulation are collection methods that are compatible with the methods and compositions disclosed herein. Cell staining may negatively affect whole genome amplification performance, especially staining methods that include fixing (e.g. with formaldehyde) steps.
(289) Sample Volume
(290) Single cells may be collected and lysed/extracted in a total of about 9 μL volume.
(291) Cell Lysis and DNA Extraction Methods
(292) Single-cell PCR lysis/extraction methods (e.g. protease/detergent incubation or alkaline treatment followed by neutralization) are compatible with the methods and compositions disclosed herein, as long as, for example, monovalent salt concentrations do not exceed 20 mM in the final 9 μL lysate volume.
(293) Considerable (>5 μL) evaporation may occur, if the incubation is being performed in a PCR plate without a very tight seal. Evaporation during PCR may be minimized by using an appropriate thermal cycler, for example, the combination of iCycler IQ 96-well PCR plates (Bio-Rad, 223-9441) and Axymat silicone sealing mats (Axygen, AM-96-PCR-RD).
(294) Exemplary Kit Components
(295) TABLE-US-00012 Component Name 1. PicoPlex Pre-Amp Buffer 2. PicoPlex Pre-Amp Enzyme 3. Pre-Amp Enzyme Dilution Buffer 4. PicoPlex Amplification Buffer 5. PicoPlex Amplification Enzyme 6. Nuclease-Free Water
(296) TABLE-US-00013 TABLE VII OLIGONUCLEOTIDE SEQUENCES USED IN SINGLE GENOME LIBRARIES PREPARATION No Sequence 5′-3′ * 1. TGTGTTGGGTGTGTTTGGKKKKKKKKKK (SEQ ID NO: 25) 2. TGTGTTGGGTGTGTTTGG (SEQ ID NO: 26) 3. TGTTGTGGGTTGTGTTGGKKKKKKKKKK (SEQ ID NO: 128) 4. TGTTGTGGGTTGTGTTGG (SEQ ID NO: 129) 5. TGTGTTGGGTGTGTTTGGNKKNKKNKK (SEQ ID NO: 130) * Random bases definitions: K = G, T; N = A, G, C, T
(297) TABLE-US-00014 TABLE VIII OLIGONUCLEOTIDE SEQUENCES USED IN LOCUS- SPECIFIC REAL-TIME PCR ASSAYS Assay No *** Sequence 5′-3′ ** 1 F AGAGGCTTCTGGCAGTTTGC (SEQ ID NO: 131) 1 R CCCAGCCTCTGGAAAATCAG (SEQ ID NO: 132) 2 F CCCTAACATGGAGGTAGGAGC (SEQ ID NO: 133) 2 R TCTTCCTGGTGTGAGCCTCT (SEQ ID NO: 134) 3 F GAGAACCGGAGCGTGCTT (SEQ ID NO: 135) 3 R TATTGACCACATGACCCCCT (SEQ ID NO: 136) 4 F GCAAAATCCATACCCTTTCTGC (SEQ ID NO: 137) 4 R TCTTTCCCTCTACAACCCTCTAACC (SEQ ID NO: 138) 5 F GCAAAATGCCTTCTTGTGTTTTTC (SEQ ID NO: 139) 5 R GCATTTTCTGTCCCACAAGATATG (SEQ ID NO: 140) 6 F ATGTTTCTCTGGCCCCAAG (SEQ ID NO: 141) 6 R TTCTCCATGAGATTGGACTGG (SEQ ID NO: 142) 10 F TCATCATGATCAACAGGAAAGA (SEQ ID NO: 143) 10 R CAACCCTGGCCTCAGGAT (SEQ ID NO: 144) 11 F GTGAATATAGTGAGTGACAGATGGC (SEQ ID NO: 145) 11 R CTTTATGAAACGGGGCCATA (SEQ ID NO: 146) 12 F CAATGTACAGGTCCTGTTGCC (SEQ ID NO: 147) 12 R AAAACAATGCTTCCAGTGGC (SEQ ID NO: 148) 13 F ACAGTCCCATTCTGGCAAAC (SEQ ID NO: 149) 13 R TCACTCCCTCCAACAATTCC (SEQ ID NO: 150) 14 F TTTGTTACTTGCTACCCTGAG (SEQ ID NO: 151) 14 R CAACCATCATCTTCCACAGTC (SEQ ID NO: 152) 15 F CGGCATGAGGAAGGTGCAGGAG (SEQ ID NO: 153) 15 R CGACACCATGCGAGACACGCTTG (SEQ ID NO: 154) 16 F AATGCCCAGCAGAACCGCC (SEQ ID NO: 155) 16 R ACTCCACAAACTCATCCAGGTCCTC (SEQ ID NO: 156) 17 F GCAAGATTTTTGCTTGGCTCTAT (SEQ ID NO: 157) 17 R CTTTGGTATTTGCTTCCACCAAC (SEQ ID NO: 158) 18 F TGAGGCTTCACATTCCAGC (SEQ ID NO: 159) 18 R TATTCCCAGTGCTGGAGAGG (SEQ ID NO: 160) 19 F TCATTGGGGCTGAGCAAT (SEQ ID NO: 161) 19 R TCAGGAGCCTTTTAGTCTGAGG (SEQ ID NO: 162) 20 F TGTTAACAATTTGCATAACAAAAGC (SEQ ID NO: 163) 20 R TGATTAATTTGCGAGACTAACTTTG (SEQ ID NO: 164) 21 F GGTTCCTCCAAAGAACAGCA (SEQ ID NO: 165) 21 R TGAGATTTGGCCTTGCTTCT (SEQ ID NO: 166) 22 F TCCATTGTTTACCCCAAAGC (SEQ ID NO: 167) 22 R TCTGGGAGTGGGAAGAGTTG (SEQ ID NO: 168) 23 F CCCAGCCCTCTCTCCGCC (SEQ ID NO: 169) 23 R CCTAAACTGGAGACGGATCCTGCCC (SEQ ID NO: 170) 24 F ACAGGCCTCCATTCATGTCCCTTCC (SEQ ID NO: 171) 24 R TCGTGGCCGCCAAGGCAC (SEQ ID NO: 172) 25 F GCATCCTATAAAAGCAGCCATGT (SEQ ID NO: 173) 25 R GGCTGAGTCATCTTCCTCTTGAA (SEQ ID NO: 174) 26 F GACCATCAGGCGACAGATT (SEQ ID NO: 175) 26 R GCTCAGGCATAACCCCTC (SEQ ID NO: 176) 28 F CTACCATGCCTGGCAGAAAT (SEQ ID NO: 177) 28 R TTGCTAACCTAAAAGACAGCAGG (SEQ ID NO: 178) 29 F TGAAAAGGATACCAAAGTGCG (SEQ ID NO: 179) 29 R TTGGGAAATGTCAGTGACCA (SEQ ID NO: 180) 30 F GGCCAACAGGAACAGCAG (SEQ ID NO: 181) 30 R TTCTCTGGATCTTTTCAGCC (SEQ ID NO: 182) 31 F CCGCGAGCTCCCTCTGCC (SEQ ID NO: 183) 31 R CTCTGTAGCCCTAGGACCGGTCTG (SEQ ID NO: 184) 32 F CTGCCGACATTCCACGGGTTTCTTG (SEQ ID NO: 185) 32 R AGCCTTCCGCTGGAAGTCCAACTTT (SEQ ID NO: 186) 33 F TTTCACATTTCCTAAGCAGCC (SEQ ID NO: 187) 33 R TTGCTTTTGCCCCCACTACTG (SEQ ID NO: 188) 34 F TGCCAGAGAAGTTTTAACAATCACA (SEQ ID NO: 189) 34 R GGATGACAACTGCTAAGGTCCAT (SEQ ID NO: 190) 35 F TATTTAAAATGTGGGCAAGATATCA (SEQ ID NO: 191) 35 R TGGTGTAAATAAAGACCTTGCTATC (SEQ ID NO: 192) 38 F CCATTTCGTATCAGTCTAGCCCA (SEQ ID NO: 193) 38 R GTCAGTGCTGCTATGGAGCTTTT (SEQ ID NO: 194) 41 F GCTTACTGATGAAAAACTCATCCA (SEQ ID NO: 195) 41 R TGGTTATAACTAACAAACCTGAACA (SEQ ID NO: 196) 42 F CTCTATGTGGCTCACGCAG (SEQ ID NO: 197) 42 R TTTACAAATGAGGGAACTCCC (SEQ ID NO: 198) 43 F TGGGAAAAGTCAGCTCGTG (SEQ ID NO: 199) 43 R AACTGGGGGCAAGAACAAC (SEQ ID NO: 200) 44 F TCATTAACACCAGTCTGCAACA (SEQ ID NO: 201) 44 R TGCAATTTGAAGGTACGAGTAG (SEQ ID NO: 202) 45 F GCACCTGCTAAGGAGGGAG (SEQ ID NO: 203) 45 R TCATTTTTTGCTGATGGTTCC (SEQ ID NO: 204) 46 F CCGCTGGATTCTTTTTCAAA (SEQ ID NO: 205) 46 R AAGGCTCAAATGCCAAATTG (SEQ ID NO: 206) 47 F AGCGGCCTGGATGAGATGCTG (SEQ ID NO: 207) 47 R CTGGTTCACAGCCCAAAGGCTGA (SEQ ID NO: 208) 48 F CTCCCACAGACCGACCAGCTTCC (SEQ ID NO: 209) 48 R GTGCATCGTGATCTCGGGTGAGAGC (SEQ ID NO: 210) * F = forward primer, R = reverse primer ** Sequences in bold represent promoter regions *** Omitted sequential numbers indicate bad quality or failed assays
(298) TABLE-US-00015 TABLE 3 Troubleshooting Guide Problem Potential Cause Suggested Solutions Sample well did not Confirm that single-cell contain a cell isolation process is properly dispensing a single cell per tube or well Single-Cell Inefficient sample lysis Use alternative lysis Amplification Curve method or EDTA-free cell Looks Like Control collection buffer. No-Cell Cell lysate contained Do not exceed 20 mM Amplification WGA inhibitors monovalent salt Curve concentration in cell lysate Cells have been Handle cells without exposed to fixatives or fixation or staining contain dye molecules Control No-Cell DNA contamination of Carefully wash cells in Amplification Curve sample fresh PBS or other serum- Appears Early free medium Exogenous DNA Clean area thoroughly and contamination in use PCR-dedicated sample or work plastics and pipettes. environment Reagents are Use fresh kit contaminated
REFERENCES
(299) All patents and publications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. All patents and publications are herein incorporated by reference in their entirety to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference.
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(302) Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.